Open Access

What attributes of extra virgin olive oil are really important for consumers: a meta-analysis of consumers’ stated preferences

  • Teresa Del Giudice1, 2Email author,
  • Carla Cavallo1, 2,
  • Francesco Caracciolo1, 2 and
  • Gianni Cicia1, 2
Agricultural and Food Economics20153:20

DOI: 10.1186/s40100-015-0034-5

Received: 26 March 2014

Accepted: 6 May 2015

Published: 24 July 2015

Abstract

The literature on food economics has extensively analyzed consumer preferences for extra-virgin olive oil attributes. In order to summarize and systematize the information gained in recent years, it seems appropriate to make a critique of the existing literature. First, we carry out a narrative systematic review of the literature on the topic. Subsequently, using only the empirical contributions which provide estimates of consumer willingness to pay for quality attributes including a measure of the goodness of the estimation (20 papers with 78 estimates), a meta-analysis was conducted to synthesize the empirical results obtained.

JEL classification

D12 C25 Q18

Keywords

Meta-analysis Consumers preferences Extra-virgin olive oil

Background

Extra-virgin olive oil (EVO) is an important element in the Mediterranean diet and a major agricultural crop for Southern European countries in terms of both farm income and cultivated area (De Graaff and Eppink 1999; Owen et al. 2000; Pupo D’Andrea, 2007; Marchini et al. 2010). Moreover, given the increased popularity of the Mediterranean diet among consumers in the US, Canada, Australia and large parts of Asia, EVO consumption has grown almost worldwide (Santosa and Guinard 2011; International Olive Oil Council 2012). Contextually, olive-oil production has switched from low yields and low-input cultivation to a capital-intensive farming system involving innovations in both agricultural practices and processing techniques. This has led to a considerable improvement in EVO nutritional characteristics accompanied by a profound change in sensory profile, turning a traditional food, with well known organoleptic features, into a brand new kind of dressing.

All the described processes have made it necessary for traders, researchers and policy makers to gain insights into consumer preferences for intrinsic and extrinsic characteristics of EVO, which have become increasingly complex and structured (Sillani et al. 2014). In recent years, this has led to a wide range of scientific contributions aiming to identify the chief EVO attributes for the postmodern consumer (Cicia et al. 2012). This research field has made extensive use of discrete choice methods based on random utility models, which help identify product characteristics most relevant to consumers, also valuing the willingness to pay for a product with such characteristics. Since the surveys were carried out in different countries, with different sample sizes, different statistical designs and often considering different choice experiment attributes as well, the results emerging from the literature are somewhat heterogeneous, although there are some well defined trends.

In order to summarize and systematize the information gained in recent years on consumer preferences related to extra-virgin olive oil, it thus seems appropriate to offer a critique of the existing literature. Our analysis can be divided into two distinct but complementary parts. The first is dedicated to a narrative systematic review of the literature on the topic. Subsequently, using 20 empirical contributions which provide estimates of consumers’ willingness to pay for quality attributes including a measure of the goodness of the estimation, a meta-analysis was conducted to synthesize the empirical results obtained.

In this paper we refer to the definitions of systematic review and meta-analysis provided by the Cochrane Collaboration (2009) and by the PRISMA Statement (Moher et al. 2009): “A systematic review is a review of a clearly formulated question that uses systematic and explicit methods to identify, select, and critically appraise relevant research, and to collect and analyze data from the studies that are included in the review. Statistical methods (meta-analysis) may or may not be used to analyze and summarize the results of the included studies. Meta-analysis refers to the use of statistical techniques in a systematic review to integrate the results of included studies”. In as much as is allowed by the subject of our analysis, in our study we followed the instructions provided by the PRISMA Statement (Moher et al. 2009) in order to carry out an appropriate review. The paper is organized as follows. In second section the narrative systematic review is described, summarizing the main results of the literature dealing with EVO attributes. The statistical model used in the meta-analysis and the empirical results are discussed in third section. Fourth section comprises the discussion, study limitations and some concluding remarks.

Narrative systematic review

The Narrative Systematic Review was carried out to summarize the literature about consumer preferences relating to EVO characteristics. The chosen period covered the years between 1994, when the first work, to our knowledge, about the subject emerged, and June 2014. The research was carried out using the main scientific/economic research databases: 1. Thomson Reuters (ISI) Web of Knowledge 2. SciVerse Scopus, 3. EconLit 4. Wiley Online Library 5. Emerald Insight 6. Google Scholar 7. AgEcon Search, 8. CiteSeerXβ 9. Microsoft Academic Search; 10. Google, Bing, Abacho, etc.

The survey identified around 78 major works which studied consumer preferences for EVO features. The scientific production related to this line of research has not appeared to decline at all. As for the countries investigated, about 73 % of the contributions focus on Mediterranean countries, which are traditionally major producers and consumers of olive oil, with Italy being the most commonly analyzed, accounting for 40 % of all contributions. The remaining 27 % of works are distributed between Northern European countries (17 %) and the rest of the world (10 %).

As regards publication type, 70 % of the articles analyzed were published in peer-reviewed journals, 20 % of contributions were presented at international conferences, and 10 % are termed final research reports. Regarding the specific contents of the various works, we can categorize the large number of articles according to two different elements. The first relates to investigation methodology, while the second concerns research questions to be solved.

Methodological approaches followed by the selected works to analyze consumer preferences show a large share of discrete choice models, applied with many variations. In particular, Conjoint Analysis and Random Utility Models (RUM) are the most widely used. As regards Conjoint Analysis, several studies have used this approach to assess the relative importance to consumers of different attributes and to define a hypothetical most preferred product (Cicia and Perla 2000; Van der Lans et al. 2001, Martínez et al. 2002; Soler et al. 2002; Krystallis and Ness 2005; Bracco et al. 2009; Jiménez-Guerrero et al. 2012; Mtimet et al. 2008, 2011, 2013; Di Vita et al. 2013; Sillani et al. 2014).

By contrast, widely adopted Random Utility Models (RUM) provide the impact of product attributes on choices and estimation of the willingness to pay (WTP) (Cicia et al. 2002; Ward et al. 2003; Scarpa and Del Giudice 2004; Cicia et al. 2005; Dekhili and d’Hauteville 2009; Finardi et al. 2009; Finardi 2010; Chan-Halbrendt et al. 2010; Menapace et al. 2011; Aprile et al. 2012; Delgado et al. 2013; Mtimet et al. 2013; Vlontzos and Duquenne 2014; Yangui et al. 2013, 2014a, 2014b).

For instance, Cicia et al. (2005) valued at one euro per bottle the attribute of Italian product origin (COOL attribute) ascribed by Italian consumers. Amongst the methodologies for analyzing consumer preferences, some studies asked interviewees to rank attributes according to their perceived importance (Del Giudice and D’Elia 2001).

Other empirical approaches adopt the hedonic price method (Karipidis et al. 2005; Ribeiro and Santos 2005; Carlucci et al. 2014) or multi-criteria analysis (Sandalidou et al. 2002; Bevilacqua et al. 2012), while others follow mainly qualitative approaches, such as means-end chains, laddering interviews or focus groups. Some interdisciplinary studies comprise features of econometric analysis and sensory analysis (McEwan 1994; Morales et al. 1997; Monteleone et al. 1997; Pagliarini et al. 1994; Caporale et al. 2004, 2006; Delgado and Guinard 2011, 2012; Finotti et al. 2007, Favati et al. 2013, Fregapane et al. 2013, Nakano et al. 2013). Finally, other modeling and theoretical frameworks comprise both qualitative analysis techniques such as laddering (Nielsen et al. 1998) and supply chain and sector analysis (Baourakis and Apostolakis 1999; Belletti and Marescotti 1998; Fucito and Vizzarri 2004; Mili and Zúñiga 2001; Mili 2006; Del Giudice et al. 2012).

As regards the aims of the selected papers, most investigated consumer preferences for specific extra-virgin olive oil attributes: they analyzed intrinsic (taste, appearance, color) and extrinsic (packaging, certifications, label, brand, etc.) product attributes. Thus, in the sections below, we highlight the main conclusions made by the literature sorted by the most commonly investigated attributes.

Olive geographical origin certification

Early studies on this topic indicated geographical origin of the olives as the main focus (McEwan 1994; Monteleone et al. 1997; Bech-Larsen et al. 1996; Belletti and Marescotti 1998; Nielsen et al. 1998; Tsakiridou et al. 2006). Geographical origin has received ever-increasing attention over the years. It has been extensively shown that, when making purchasing decisions, consumers, albeit from different geographical and socio-economic realities, attach a priority value to information about the country of origin of the olives concerned (Nielsen et al. 1998; Van der Lans et al. 2001; Fotopoulos and Krystallis 2002; Krystallis and Ness 2005; Ward et al. 2003; Scarpa et al. 2005; Gázquez‐Abad and Sánchez‐Pérez 2009; Del Giudice and D’Elia 2001, Dekhili et al. 2011; Aprile et al. 2012; Piccolo et al. 2013).

The Geographical Origin attribute was also analyzed through the study of influences exerted by Community certification of origin (PDO and PGI, EC Regulation 509/06 and 510/06) on individual preferences. Several studies agree on two common conclusions (Van der Lans et al. 2001; Scarpa and Del Giudice 2004; Menapace et al. 2008; Bracco et al. 2009; Fucito and Vizzarri 2004; Finco et al. 2010).

The first conclusion concerns the considerable importance of olive origin as a key element in individual choices. In many markets, origin indication is synonymous with a local product. Consumers seem to prefer, regardless of other items, the typical product of the area of consumption. Since the sensory characteristics of olive oil and extra-virgin olive oil are greatly affected by cultivars and agronomic techniques, knowledge of origin gives the consumer assurances concerning product taste characteristics.

The second conclusion is that EC designations of origin (PDO and PGI) have never fully expressed their potential as differentiation and protection tools. Indeed, they are still little known to consumers, who continue to use other quality signals and origin certification, such as trademarks evocative of particular production areas, trademarks traditionally associated with specific origins, certification of private standards focused on olives origin or label information about bottling location, which often, before the recent legislation came into force (EU Reg. 182/09 and EU Reg. 1169/2011), was unrelated to the source of olives.

Product food safety

A second group of attributes, which has received wide attention from papers discussing EVO health aspects, consists in food safety and traceability. This line of research also includes attention toward organic certification. This attribute has a twofold value for the consumer: first it indicates attention toward health and preservation of the natural environment (Cicia et al. 2009). Organic certification has been shown to be positively perceived by consumers, although more than twenty years after EU regulation on organic produce and its definition came into force, consumer information levels were still unsatisfactory (Van der Lans et al. 2001; Soler et al. 2002; Fotopoulos and Krystallis 2002; Cicia et al. 2002; Zanoli et al. 2002; Sandalidou et al. 2002; Del Giudice et al. 2012).

In more recent works, the relation between origin and traceability emerges quite strongly (Leonetti et al., 2009; Chan-Halbrendt et al. 2010; Mane-Kapaj et al. 2010; Gázquez‐Abad and Sánchez‐Pérez 2009; Cicia et al. 2005; Menapace et al. 2008; Deselnicu et al. 2013; Gambaro et al. 2013). Traceability and related labeling information have become increasingly analyzed elements. Traceability means the ability to track food through all stages of production, processing and distribution. Traceability was introduced by the EU’s General Food Law (EC Reg. 178/2002). It has been generally shown that information on traceability influences consumer choices, which are ever more geared to food safety (Soler et al. 2002; Krystallis and Ness, 2005). However, the studies in question indicate that consumers consider information about the origin of the olives the most important element for traceability of the product. Knowledge of all stages of production, processing and distribution does not seem to affect consumer choice, the information about the origin of the raw material seems more important (Cicia et al. 2005; Di Vita et al. 2013).

Brand

Another relevant attribute within consumer preferences is represented by brand (Baourakis and Baltas 2003; Bower et al. 2003; Del Giudice and D’Elia 2001; Cicia et al. 2005; Bracco et al. 2009; Dekhili and d’Hauteville 2009; Gázquez‐Abad and Sánchez‐Pérez 2009; Jiménez-Guerrero et al. 2012). In particular, the literature highlights the preference of consumers for traditionally known brands and private labels, both with an increasing information value and reassuring features for the consumer.

Price

Price clearly emerges as a “particular” attribute as stated by the literature, with regard to the influence upon purchase choices and on perception of extra-virgin olive oil quality. Indeed, several studies have shown the considerable attention paid to price on the part of consumers (McEwan 1994; Baourakis and Apostolakis, 1999; Baourakis and Baltas 2003; Lazaridis 2004; Gázquez‐Abad and Sánchez‐Pérez 2009, Carlucci et al. 2014). Other studies (Cicia et al. 2002; Martínez et al. 2002; Scarpa and Del Giudice 2004) highlight the role played by the price factor as a quality indicator for extra-virgin olive oil. Indeed, very often the preference toward this attribute seems to follow a triangular path typical of quality products (Cicia and Perla 2000).

Sensory attributes

The last group of attributes analyzed comprises all product sensory and taste aspects. This kind of analysis showed significant changes over the period. In general, in the past, olive oil taste and color were considered two of the attributes that most influenced consumer perception and purchase choice, without, however, identifying them individually as being present (McEwan 1994; Finotti et al. 2007; Monteleone et al. 1997; Cicia et al. 2002).

Further developments in the way EVO sensory and taste aspects are described and researched both at production and processing level have led to in-depth analysis of consumer preferences. On the production side there has been a trend toward oils which, thanks to innovations in production techniques introduced over the past two decades, result in a product with enhanced sensory characteristics (pungent, bitter, fruity, etc.). On the consumption side, because of the strong link with traditional preferences and thanks to the educational role played by branded products and GDO private labels toward tasting, there is now a generation of EVO users who seem to prefer a product with a quite plain, neutral taste, generating a serious split in the market (Leonetti et al. 2009; Santosa et al. 2010; Mtimet et al. 2008, 2011, 2013; Caporale et al. 2006; Delgado and Guinard 2011, 2012; Delgado et al. 2013; Recchia et al. 2012; Bevilacqua et al. 2012; Del Giudice et al. 2012).

Econometric meta-analysis

Meta-analysis is increasingly proving that it could play a valuable role in objectively and effectively exploring topics which are extensively debated in the scientific literature. Meta-analysis as a tool for scientific investigation was first used in the early 20th century (Simpson and Pearson 1904), although the term itself was first coined only in 1976 (Glass 1976).

This approach has also benefited in recent years from the process that has led to massive web indexing and sharing of the results of scientific research. Although its main application is in the medical sciences, studies focusing on meta-analysis are becoming more widespread and accepted in other disciplines, including economics and social sciences (Nelson and Kennedy 2009).

It is undeniable that having a comprehensive and objective view of what research has produced on the subject of interest over the years represents the first stage for any researcher interested in providing a new contribution to knowledge, taking advantage of the spillover offered by previous scientific productiona. With regard to the analysis of consumer EVO preferences, both quality and quantity of scientific output allow the main results to be synthesized and systematized. Within this scope, a meta-analysis study, thanks to the characteristics of the regression models in terms of inference on reality, seems an efficient choice. Therefore, the aim of the meta-analysis proposed herein is to provide a statistically rigorous synopsis of the findings in the literature on consumer preferences for extra virgin olive oil attributes.

Our approach analyzes the WTP of consumers for several EVO attributes. As previously stated, many studies on this subject adopt the discrete choice method based on random utility theoryb. If the price is included among the attributes, it is thus possible to obtain the preference for the various attributes considered, measured in monetary terms, as WTP. However, direct comparison among studies of WTPs for the various attributes is not strictly feasible in these terms as the results of each estimation are in local currency and they refer to specific space-time situations.

In light of the above considerations, the variable of interest, or the dependent variable of our model, WTP, was transformed into the relative change with respect to the base price of EVO as reported in each specific study. Meta-analysis may thus summarize the general indications on willingness to pay for different attributes by using results from studies from different sites, surveys, methodologies, and sample characteristics.

From an empirical point of view, not all the analyzed studies provided information directly usable for our purpose: only 20 studies explicitly provided the estimated WTP including a measure of the variance of the estimation, information necessary for implementation of random or fixed-effect models. Since each study usually considers jointly the preferences for different attributes, thus providing several estimates of WTP, our meta-analysis collected 78 WTPs overall from 20 studies written during the decade 2004–2014 (see Table 3). In order to avoid publication bias, also “non peer-reviewed articles” were included in the meta-analysis (Duval and Tweedie 2000; Rothstein et al. 2006). The explanatory variables used in the meta-analysis are shown in Table 1 with some descriptive statistics.
Table 1

Explanatory variables used in the meta-analysis

Variable

Mean value

Min

Max

WTP (relative variation)

0.46

−0.92

0.98

Olive Origin certification

0.30

0

1

Brand

0.10

0

1

Neutral taste

0.15

0

1

Traceability

0.07

0

1

Organic Certification

0.12

0

1

Peer-reviewed article

0.60

0

1

Italy-based survey

0.30

0

1

There are three parametric methods most widely used within meta-analysis: 1. Linear regression analysis model (or meta-regression); 2. Fixed-effect meta-regression analysis; 3. Random-effect meta-regression analysis.

The Linear regression analysis model (or meta-regression) follows the ordinary least squares approach. Specifically, we assume that each i-study of n total studies provided an estimate of the relative willingness to pay equal to WTP i :
$$ WT{P}_i={\mathbf{x}}_i\boldsymbol{\upbeta} +{u}_i,\mathrm{with}{u}_i \sim N\left(0,{\upsigma}^2\right) $$
(1)

where x i is a 1 × k vector of covariates (including intercept) that characterizes the study i and β is a k × 1 coefficient vector. Standard error estimates are provided through a bootstrap procedure to prevent possible estimation bias due to heteroskedasticity.

Meta-regression assumes that all the estimates of WTP included in the meta-analysis have the same precision or variability. When the confidence interval or the variance of WTP is available, it may be taken into account by adopting a variance weighted OLS. The literature on meta-analysis refers to this specification as Fixed-effect meta-regression analysis. In this case Eq. 1 becomes:
$$ WT{P}_i = {\mathbf{x}}_i\boldsymbol{\upbeta} + {e}_i,\ \mathrm{with}{e}_i\sim N\left(0,{\upsigma^2}_{\mathrm{i}}\right) $$
(2)

Equation 2 can be estimated by weighted least squares, with the weights 1/ σ2 i where σ2 i is the estimated variance of the parameter provided by the i-th study.

However, by construction, fixed effect meta-regression analysis assumes that between-study variability of the estimates are equal to zero. In order to overcome this limitation random effect meta-regression analysis estimates a new parameter (τ2) for taking between-study variability into account:
$$ WT{P}_i={\mathbf{x}}_i\boldsymbol{\upbeta} +{e}_i+{u}_i,\ \mathrm{with}{u}_i\sim N\left(0,{\uptau}^2\right)\ \mathrm{and}{e}_i \sim N\left(0,{\upsigma^2}_{\mathrm{i}}\right) $$
(3)

The estimation procedure of Eq. (3) consists of a first estimate of τ2 (variance between studies) and then in an estimate of the coefficients β through the least squares method weighted by using 1/(σ2 i + τ2) as weights. The algorithm is iterative and follows the procedure suggested by Thompson and Sharp (1999).

In particular, having set an initial value for τ2, the estimate of τ2 is based on the following log-likelihood function maximization:
$$ {\mathrm{L}}_{\mathrm{R}}\left({\uptau}^2\right) = -\frac{1}{2}{\displaystyle \sum_i\left\{ \log \left({\sigma}_i^2+{\tau}^2\right)+\frac{{\left({y}_i-{\mathbf{x}}_i\widehat{\boldsymbol{\upbeta}}\right)}^2}{\sigma_i^2+{\tau}^2}\right\}-\frac{1}{2}} \log \left|\mathbf{X}\hbox{'}{\mathbf{V}}^{\hbox{-} 1}\mathbf{X}\right| $$

where \( \mathbf{V}= diag\left({\sigma}_1^2+{\tau}^2,{\sigma}_2^2+{\tau}^2,\dots, {\sigma}_n^2+{\tau}^2\right) \) and \( \widehat{\boldsymbol{\upbeta}}={\left(\mathbf{X}\hbox{'}{\mathbf{V}}^{-1}\mathbf{X}\right)}^{-1}\mathbf{X}\hbox{'}{\mathbf{V}}^{-\mathbf{1}}\mathbf{y} \) (Harville 1977).

From the sum of the squares of the weighted errors, \( {Q}_E={{\displaystyle \sum_i\left(\frac{y_i-{\mathbf{x}}_i\widehat{\boldsymbol{\upbeta}}}{\sigma_i}\right)}}^2 \) (Lipsey and Wilson 2001) it is possible to calculate the measure of the percentage of the residual variation that is attributable to between-study heterogeneity:
$$ {I}^2= \max \left\{\frac{Q_E-\left(n-k\right)}{Q_E},0\right\}. $$

The last two models are particularly useful when the purpose of studies is to estimate the “size effect” (effectiveness of a medicinal product, willingness to pay for a food attribute, etc.), exploiting the information from the confidence intervals of the measure.

In this specific study we apply all three models. For the estimation of the last two models we also use a measure of the variance of the WTP as estimated in the individual studies, in order to weight the effect size of each case study with an index of the goodness of the estimate.

Table 2 reports the results of the three estimates. All the exogenous variables considered show the same direction in the three different specifications. Of the three specifications, the fixed-effect meta-regression model seems to perform best, showing overall a higher significance level of the coefficients. This result is formally confirmed by the Cochran (QE) test and by the Higgins heterogeneity measure (I2) (Higgins and Green 2008). This specific result supports the outcomes of the “fixed effects model”, implying the existence of a “true effect size” similar for all the studies, and the WTP differences reported in several studies are not statistically significant. In other words, the variation in the WTP for the attributes would appear the same for all studies, albeit conducted in different countries and at different times.
Table 2

Assessment of implemented econometric models

Variable

Meta-regression

Fixed effect meta-regression

Random effect meta-regression

 

Coeff

std-dev

Coeff

std-dev

Coeff

std-dev

Olive origin certification

0.474***

0.144

0.489***

0.151

0.496***

0.107

Brand

0.521**

0.243

0.608***

0.207

0.531***

0.193

Neutral taste

0.251

0.173

0.197***

0.056

0.194

0.21

Traceability

0.033

0.041

0.145

0.105

0.12

0.08

Organic certification

0.393*

0.215

0.577***

0.139

0.403

0.32

Peer-reviewed article

−0.276

0.192

−0.355***

0.124

−0.324***

0.096

Italy-based survey

−0.416***

0.112

−0.646***

0.238

−0.459***

0.143

Constant

0.579

0.439

0.12

0.215

0.245

0.201

R2

0.3078

 

0.3192

   

τ2

    

0.029

 

I 2

    

15.20 %

 

Adj R2

    

81.28 %

 

QE

    

64.37 (χ2 89.39; df 69; p<0.05)

 

F (8, 69)

3.84

 

4.05

 

8.05

 

Prob>F

0.0009

 

0.0005

 

<0.0001

 

#obs: 78 || *p<0.1; **p<0.05; ***p<0.01.

Table 3

List of studies included in the meta-regression analysis

Authors

Year

Title

Source title

Publication type (report, peer-reviewed article, etc.)

Study area

G. Cicia e C. Perla

2000

La percezione della qualità nei consumatori di prodotti biologici: uno studio sull’olio extra-vergine di oliva tramite conjoint analisys

Qualità e valorizzazione nel mercato dei prodotti agroalimentari tipici

Book chapter

Italy

I. van der Lans, K. van Ittersum, A. De Cicco, M. Loseby

2001

The role of the region of origin and EU certificates of origin in consumer evaluation of food products

European Review of Agricultural Economics

Peer-reviewed article

Italy

G. Cicia, T. Del Giudice, R. Scarpa

2002

Consumers’ perception of quality in organic food A random utility model under preference heterogeneity and choice correlation from rank-orderings

British Food Journal

Peer-reviewed article

Italy

R. W. Ward, J. Briz, I. de Felipe

2003

Competing Supplies of Olive Oil in the German Market: An Application of Multinomial Logit Models

Agribusiness

Peer-reviewed article

Germany

R. Scarpa, T. Del Giudice

2004

Market Segmentation via Mixed Logit: Extra-Virgin Olive Oil in Urban Italy

Journal of Agricultural & Food Industrial Organization

Peer-reviewed article

Italy

G. Cicia, T. Del Giudice, R. Scarpa

2005

Welfare Loss due to Lack of Traceability in Extra-virgin Olive Oil: a Case Study

Cahiers Options Méditerranéennes

Peer-reviewed article

Italy

S. Dekhili, F. D’Hauteville

2009

Effect of the region of origin on the perceived quality of olive oil: An experimental approach using a control group

Food Quality and Preference

Peer-reviewed article

Tunisia-France

C. Finardi, C. Giacomini, D. Menozzi, C. Mora

2009

Consumer preferences for country-of-origin and health claim labelling of extra-virgin olive-oil

113th EAAE Seminar “A resilient European food industry and food chain in a challenging world”

Conference paper

Italy

C. Chan-Halbrendt E. Zhllima, G. Sisior, D. Imami, L. Leonetti

2010

Consumer Preferences for Olive Oil in Tirana, Albania

International Food and Agribusiness Management Review

Peer-reviewed article

Albania

C. Finardi

2010

Preferenze dei consumatori per attributi di qualità dell’olio extravergine di oliva. Una indagine empirica

AgriRegioniEuropa

Peer-reviewed article

Italy

L. Menapace, G. Colson, C. Grebitus, M. Facendola

2011

Consumers’ preferences for geographical origin labels: evidence from the Canadian olive oil market

European Review of Agricultural Economics

Peer-reviewed article

Canada

N. Mtimet, K. Ujiie, K. Kashiwaghi, L. Zaibet, M. Nagaki

2011

The effects of Information and Country of Origin on Japanese Olive Oil Consumer Selection

EAAE 2011 Congress “Change and Uncertainty Challenges for Agriculture, Food and Natural Resources”

Conference paper

Japan

M.C. Aprile, V. Caputo, R.M. Jr. Nayga

2012

Consumers’ valuation of food quality labels: the case of the European geographic indication and organic farming labels

International journal of consumer studies

Peer-reviewed article

Italy

C. Delgado, A. Gomez-Rico, J.X. Guinard

2013

Evaluating bottles and labels versus tasting the oils blind: Effects of packaging and labeling on consumer preferences, purchase intentions and expectations for extra virgin olive oil

Food Research International

Peer-reviewed article

USA/California

G. Di Vita, M. D’Amico, G. La Via, E. Caniglia

2013

Quality Perception of PDO extra-virgin Olive Oil: Which attributes most influence. Italian consumers?

Agricultural Economics Review

Peer-reviewed article

Italy

A. Yangui, M. Costa-Font, J.M. Gil

2013

The effect of food related personality traits and lifestyle orientation on consumer’s behavior related to extra virgin olive oil: estimation of an extended hybrid choice model

4th ICAAAE

Conference Paper

Spain

N. Mtimet, L. Zaibet, C. Zairi, H. Hzami

2013

Marketing Olive Oil Products in the Tunisian Local Market: The Importance of Quality Attributes and Consumers’ Behavior

Journal of International Food & Agribusiness Marketing

Peer-reviewed article

Tunisia

G. Vlontzos, M.N. Duquenne

2014

Assess the impact of subjective norms of consumers’ behaviour in the Greek olive oil market

Journal of Retailing and Consumer Services

Peer-reviewed article

Greece

A. Yangui, M. Costa-Font, J.M. Gil

2014

Revealing additional preference heterogeneity with an extended random parameter logit model: the case of extra virgin olive oil

Spanish Journal of Agricultural Research

Peer-reviewed article

Spain

A. Yangui, F. Akaichi, M. Costa-Font, J.M. Gil

2014

Are ranking preferences information methods comparable with the choice experiment information in predicting actual behavior?

EAAE 2014 Congress

Conference Paper

Spain

This result might arise from the specific design of the dependent variable as a percentage change with respect to a base price. By using this procedure the differences between the estimates based on study-specific characteristics might be minimized.

The results of our meta-analysis indicate that known brand, organic certification, olive origin certification (including European PDO, PGI and private certifications of country of origin) and neutral taste have a positive influence on consumers’ WTP. The opposite consideration can be made for articles published in peer-reviewed journals, and those referring to Italian consumers. Thus Italian consumers show overall less importance to quality attributes compared to consumers from other countriesc, while articles not published in peer-reviewed journals seem to overestimate the real WTP for the attributes. A possible explanation could be related to the difficulty being published in a peer review journal since higher WTP estimates are considered less reliable. Finally, traceability does not seem to influence WTP. This result is related to the greater influence that information on the area of origin has on consumer choices. Information on the origin of the olives seems the most important aspect of traceability for EVO consumers. Coefficients measure the relative variation of the final price of EVO in terms of WTP, and therefore can be interpreted also as measure of importance for the consumers of the attributes. This means that brand, organic certification and origin certification can be considered the product attributes showing the greatest influence on consumer willingness to pay. Finally, the neutral taste attribute shows the lowest WTP.

Conclusions

Analysis of the literature on EVO consumer preferences and the meta-analysis implemented on the information attained allow some interesting considerations to be made. The first concerns the importance of the research strand which continues to interest not only traditional producer and consumer countries but also new geographical areas, such as China and Japan, which have only recently discovered the product’s nutritional and gustatory value. The second concerns the evolution of factors/characteristics which have, over the years, been the subject of the literature. Constant value across the period in question is to be attributed to origin certification, in all its various specifications (PDO, PGI, and private certifications of country of origin) and, to a lesser extent, to the known brand. Such attributes represented the cardinal points of our analysis. In all the studies, as also shown by meta-analysis, origin and brand decidedly affect consumer preferences. In particular, all the studies carried out have shown unequivocally the strategic role played by knowledge, on the part of the end purchaser, of the oil’s origin. This situation appeared so evident that the European Union issued EC Regulation 182/09 in 2009 with the aim of making information on product origin clear and mandatory on the label. This new regulatory scenario combined with what was already written on the known origin of the extra-virgin olive oil excludes this characteristic from the possible focuses of further innovative research. Investigating how product origin may affect purchases of extra-virgin oil becomes a question of valid research especially if the study is carried out in countries such as China, India or other economies considered potential wealthy markets for the product in question.

Brand is another important attribute: in recent years the role of private labels has acquired major strategic value. Indeed, national and international brands of the large retailers, thanks to the reputation that they have built up, manage to supply the consumer with a guarantee not only of organoleptic quality and food safety but also of environmental (integrated production with the use of low input) and social sustainability (ethical certifications like SA8000). Organic certification represents an element of product differentiation, related to safety and the environment, which the consumer clearly appreciates.

The third reflection concerns aspects of taste in the literature. Indeed, while in older contributions intrinsic attributes were explored without particular focus on the various specifications which they might assume, recent analyses have begun to define the various dimensions of the sensory profile of EVOs. This evolution is due to developments which have occurred in the sensory analysis of olive oil and in the use of panel tests as a monitoring tool and guide in quality oil production. To date, agronomic and sensory research has managed not only to identify what aspects of taste and smell are indicators of oil quality but also how the latter correlate with production techniques The situation which currently emerges is that a quality EVO has a sensory profile which is quite marked and well differentiated. By contrast, on the consumption side, the consumer prefers standard oils with little or no personality. This is amply highlighted by the results of the econometric model where neutral taste is ranked fourth in importance, after brand, organic certification and origin certification. This probably represents the question of the most topical interest. This aspect deserves a central position in future research since consumption preferences as described undermine all efforts to improve product quality made on the production side. Indeed, at present on the EVO market there is a serious discrepancy: producers who invested heavily in the past in improving product quality have had to overhaul their traditional production techniques, rewarded by the “experts” and “punished” by the market.

Finally, mention should be made of the limitations to the analysis. The first concerns the large number of studies, included in the econometric model, implemented in the countries where EVO is traditionally consumed. By contrast, consumer preferences for EVO in new markets, such as Asia, the US and Japan, have so far undergone little analysis.

The second is related to the number of papers included in the econometric analysis. Moreover, the sample size, although adequate for the objectives and the econometric approach of the analysis, did not allow the introduction of additional attributes in the econometric model considered.

A possible development of the analysis may involve the inclusion of papers belonging to a longer time period. This would allow the implementation of analytical models that can provide information on the evolution and changes in consumer preferences.

Endnotes

aIf I have seen far, it is by standing on the shoulders of giants” (Isaac Newton, 1676).

bAn anonymous referee suggested including in the analysis estimates of “implicit prices” provided by hedonic price modeling as done by Deselnicu et al. (2013). Following the arguments provided by Brander and Koetse (2011) we included in our analyses only WTPs provided by stated preference techniques. This decision is also supported by the scarcity of available estimates using hedonic pricing (Carlucci et al. 2014).

cOne possible interpretation on the less importance to quality attributes given by Italian consumers could be associated to the fact that being Italy a producer country the oil olive price is on average lower than other non producing countries, and therefore also the WTP for the single attribute. However as highlighted by an anonymous referee, the same is not observed in other producer countries. Further investigations would be necessary on this specific point.

Declarations

Acknowledgements

Research funded by the Italian Ministry of Agriculture (MiPAAF). Project: “Modelli statistici innovativi per la misura della Customer Satisfaction dei prodotti agro-alimentari: il caso dell’olio extra-vergine di oliva”.

Authors’ Affiliations

(1)
Department of Agricultural Sciences, University of Naples Federico II
(2)
MiPAAF – ex Centro per la Formazione in Economia e Politica dello Sviluppo Rurale

References

  1. Aprile MC, Caputo V, Nayga RM Jr (2012) Consumers’ valuation of food quality labels: the case of the European geographic indication and organic farming labels. Int J Consum Stud 36(2):158–165View ArticleGoogle Scholar
  2. Baourakis G, Apostolakis I (1999) A statistical assessment of consumers’ criteria regarding organic agricultural products: the case of organic olive oil. Foundations Comput Decis Sci 24:21–31Google Scholar
  3. Baourakis G, Baltas G (2003) Comparative behavioural analysis in selected EU countries: a brand modelling approach. Oper Res 3(2):165–182Google Scholar
  4. Bech-Larsen T, Nielsen NA, Grunert KG (1996) Means-End Chains for low involvement food products: a study of Danish consumers’ cognitions regarding different applications of vegetable oil. In: 21st Annual IAREP Conference, Social and Economic Representations, ParisGoogle Scholar
  5. Belletti G, Marescotti A (1998) The reorganization of trade channels of a typical product : the Tuscan extra-virgin olive-oil. In: Arfini F, Mora C (eds) Typical and traditional products: rural effect and Agro-industrial problems, Proceedings of the 52nd Seminar of the EAAE - European Association of Agricultural Economists, June 19-21 1997. Università di Parma, Istituto di Economia Agraria e Forestale, Parma, Italy, pp 271–286Google Scholar
  6. Bevilacqua M, Ciarapica FE, Marchetti B (2012) Development and test of a new fuzzy-QFD approach for characterizing customers rating of extra virgin olive oil. Food Qual Preference 24(1):75–84View ArticleGoogle Scholar
  7. Bower JA, Saadat MA, Whitten C (2003) Effect of liking, information and consumer characteristics on purchase intention and willingness to pay more for a fat spread with a proven health benefit. Food Qual Preference 14(1):65–74View ArticleGoogle Scholar
  8. Bracco C, Caniglia E, D’Amico M, Di Vita G, Pappalardo G (2009) Analisi del consumo e percezione della qualità dell’olio extravergine d’oliva biologico in Italia. In: Agricoltura Biologica: sistemi produttivi e modelli di commercializzazione e consumo Palermo: Università degli Studi di Palermo, Dipartimento di Economia dei Sistemi Agro ForestaliGoogle Scholar
  9. Brander LM, Koetse MJ (2011) The value of urban open space: Meta-analyses of contingent valuation and hedonic pricing results. J Environ Manage 92(10):2763–2773View ArticleGoogle Scholar
  10. Caporale G, Policastro S, Monteleone E (2004) Bitterness enhancement induced by cut grass odorant (cis-3-hexen-1-ol) in a model olive oil. Food Qual Preference 15(3):219–227View ArticleGoogle Scholar
  11. Caporale G, Policastro S, Carlucci A, Monteleone E (2006) Consumer expectations for sensory properties in virgin olive oils. Food Qual Preference 17(1):116–125View ArticleGoogle Scholar
  12. Carlucci D, De Gennaro B, Roselli L, Seccia A (2014) E-commerce retail of extra virgin olive oil: an hedonic analysis of Italian SMEs supply. Br Food J 116(10):1600–1617View ArticleGoogle Scholar
  13. Chan-Halbrendt C, Zhllimab E, Sisiorc G, Imamid D, Leonettie L (2010) Consumer preferences for olive oil in Tirana, Albania. Int Food Agribusiness Manage Rev 13:3Google Scholar
  14. Cicia G, Perla C (2000) La percezione della qualità nei consumatori di prodotti biologici: uno studio sull’olio extra-vergine di oliva tramite conjoint analysis. Qualità e valorizzazione nel mercato dei prodotti agroalimentari tipici, Edizioni Scientifiche Italiane, Napoli, pp 237–252Google Scholar
  15. Cicia G, Del Giudice T, Scarpa R (2002) Consumers’ perception of quality in organic food: a random utility model under preference heterogeneity and choice correlation from rank-orderings. Br Food J 104(3/4/5):200–213View ArticleGoogle Scholar
  16. Cicia G, Del Giudice T, Scarpa R (2005) Welfare Loss due to lack of traceability in extra-virgin olive oil: a case study. Cahiers Options Méditerranéennes 64:19–32Google Scholar
  17. Cicia G, Del Giudice T, Ramunno I (2009) Environmental and health components in consumer perception of organic products: Estimation of willingness to pay. J Food Prod Mark 15(3):324–336View ArticleGoogle Scholar
  18. Cicia G, Cembalo L, Del Giudice T, Verneau F (2012) Il sistema agroalimentare ed il consumatore postmoderno: nuove sfide per la ricerca e per il mercato. Economia agro-alimentare 1:117–142Google Scholar
  19. Commission of the European Communities (2006a) Council Regulation (EC) No 509/2006 of 20 March 2006 on agricultural products and foodstuffs as traditional specialties guaranteed. Off J Eur Union L93:1–11Google Scholar
  20. Commission of the European Communities (2006b) Council Regulation (EC) No 510/2006 of 20 March 2006 on the protection of geographical indications and designations of origin for agricultural products and foodstuffs. Off J Eur Union L93:12–25Google Scholar
  21. Commission of the European Communities (2009) Council Regulation (EC) No 182/2009 of 6 March 2009 amending Regulation (EC) No 1019/2002 on marketing standard for olive oil. Off J Eur Union L63:6–8Google Scholar
  22. De Graaff J, Eppink L (1999) Olive oil production and soil conservation in southern Spain, in relation to EU subsidy policies. Land Use Policy 16(4):259–267View ArticleGoogle Scholar
  23. Dekhili S, d’Hauteville F (2009) Effect of the region of origin on the perceived quality of olive oil: an experimental approach using a control group. Food Qual Preference 20(7):525–532View ArticleGoogle Scholar
  24. Dekhili S, Sirieix L, Cohen E (2011) How consumers choose olive oil: the importance of origin cues. Food Qual Preference 22(8):757–762View ArticleGoogle Scholar
  25. Del Giudice T, D’Elia A (2001) Valorizzazione dell’olio extravergine d’oliva meridionale: una proposta metodologica per l’analisi delle preferenze. Rivista di Economia Agraria 56(4):11–42Google Scholar
  26. Del Giudice T, Panico T, Caracciolo F, Cicia G (2012) Le preferenze dei consumatori italiani nei confronti dell’attributo biologico nell’olio extra-vergine di oliva alla luce della nuova normativa sull’etichettatura. In: V Workshop Nazionale GRAB-IT 2012, Ancona, 10–11 May 2012Google Scholar
  27. Delgado C, Guinard J-X (2011) How do consumer hedonic ratings for extra virgin olive oil relate to quality ratings by experts and descriptive analysis ratings? Food Qual Preference 22(2):213–225View ArticleGoogle Scholar
  28. Delgado C, Guinard JX (2012) Internal and external quality mapping as a new approach to the evaluation of sensory quality-a case study with olive oil. J Sens Stud 27(5):332–343View ArticleGoogle Scholar
  29. Delgado C, Gómez-Rico A, Guinard J-X (2013) Evaluating bottles and labels versus tasting the oils blind: effects of packaging and labeling on consumer preferences, purchase intentions and expectations for extra virgin olive oil. Food Res Int 54(2):2112–2121View ArticleGoogle Scholar
  30. Deselnicu OC, Costanigro M, Souza-Monteiro DM, McFadden DT (2013) A meta-analysis of geographical indication food valuation studies: what drives the premium for origin-based labels? J Agric Resour Econ 38(2):204–219Google Scholar
  31. Di Vita G, D’Amico M, La Via G, Caniglia E (2013) Quality perception of PDO extra-virgin olive oil: which attributes most influence Italian consumer. Agric Econ Rev 14(2):46–58Google Scholar
  32. Duval S, Tweedie R (2000) Trim and fill: a simple funnel‐plot-based method of testing and adjusting for publication bias in meta‐analysis. Biometrics 56(2):455–463View ArticleGoogle Scholar
  33. Favati F, Condelli N, Galgano F, Caruso MC (2013) Extra virgin olive oil bitterness evaluation by sensory and chemical analyses. Food Chem 139(1):949–954View ArticleGoogle Scholar
  34. Finardi C (2010) Preferenze dei consumatori per attributi di qualità nell’olio extravergine di oliva. Un choice experiment. (Doctoral Dissertation), Retrieved from http://dspace-unipr.cineca.it/
  35. Finardi C, Giacomini C, Menozzi D, Mora C (2009) Consumer preferences for country-of-origin and health claim labelling of extra-virgin olive-oil. In: 113rd EAAE Seminar on: “A resilient European food industry and food chain in a chal-lenging world”, 3–6 September, Chania (Greece)Google Scholar
  36. Finco A, Padella M, Sargentoni T (2010) Disponibilità a pagare per la qualità di un olio extravergine locale. Economia Agro-alimentare 12(1):77–98Google Scholar
  37. Finotti E, Bersani AM, Bersani E (2007) Total quality indexes for extra‐virgin olive oils. J Food Qual 30(6):911–931View ArticleGoogle Scholar
  38. Fotopoulos C, Krystallis A (2002) Purchasing motives and profile of the Greek organic consumer: a countrywide survey. Br Food J 104(9):730–765View ArticleGoogle Scholar
  39. Fregapane G, Gómez‐Rico A, Inarejos AM, Salvador MD (2013) Relevance of minor components stability in commercial olive oil quality during the market period. Eur J Lipid Sci Technol 115(5):541–548View ArticleGoogle Scholar
  40. Fucito R, Vizzarri G (2004) Strategie d’impresa e qualità nel comparto degli oli extra-vergini di oliva molisani. In: Centro studi di estimo e di economia territoriale-ce set, 44th edn., pp 49–81Google Scholar
  41. Gambaro A, Ana CE, Victor P (2013) Influence of subjective knowledge, objective knowledge and health consciousness on olive oil consumption°™a case study. Food Nutr Sci Vol.04No.04:9. doi:10.4236/fns.2013.44057Google Scholar
  42. Gázquez‐Abad JC, Sánchez‐Pérez M (2009) Factors influencing olive oil brand choice in Spain: an empirical analysis using scanner data. Agribusiness 25(1):36–55View ArticleGoogle Scholar
  43. Glass GV (1976) Primary, secondary, and meta-analysis of research. In: Educational researcher., pp 3–8Google Scholar
  44. Harville DA (1977) Maximum likelihood approaches to variance component estimation and to related problems. J Am Stat Assoc 72(358):320–338View ArticleGoogle Scholar
  45. Higgins JPT, Green S (2008) Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration. Available from www.cochrane-handbook.org
  46. International Olive Oil Council (2012) Table 4: Consumption (1000 tonnes)., http://www.internationaloliveoil.org/documents/viewfile/4190-consommation1/3. Accessed 11 October 2014Google Scholar
  47. Jiménez-Guerrero JF, Gázquez-Abad JC, Mondéjar-Jiménez JA and Huertas-García R (2012). Consumer Preferences for Olive-Oil Attributes: A Review of the Empirical Literature Using a Conjoint Approach, Olive Oil - Constituents, Quality, Health Properties and Bioconversions, Dr. Dimitrios Boskou (Ed.), ISBN: 978-953-307-921-9, InTech. Available from: http://www.intechopen.com/books/olive-oil-constituents-quality-health-propertiesand-bioconversions/consumer-preferences-for-olive-oil-attributes-a-review-of-the-empiricalliterature-using-a-conjoint.
  48. Karipidis P, Tsakiridou E, Tabakis N (2005) The Greek olive oil market structure. Agric Econ Rev 6(1):64Google Scholar
  49. Krystallis A, Ness M (2005) Consumer preferences for quality foods from a South European perspective: a conjoint analysis implementation on Greek olive oil. Int Food Agribusiness Manage Rev 8(2):62–91Google Scholar
  50. Lazaridis P (2004) Olive oil consumption in Greece: a microeconometric analysis. J Fam Econ Issues 25(3):411–430View ArticleGoogle Scholar
  51. Leonetti L, Imami D, Stefanllari A, Zhllima E (2009) The olive and olive oil value chain In Albania. Development Solutions Associates., Available via EastAgri. http://www.eastagri.org/files/Oil-Albania.pdf. Accessed 2 October 2014Google Scholar
  52. Lipsey MW, Wilson DB (2001) Applied social research methods series. In: Practical meta-analysis, 49th edn. Sage Publications, LondonGoogle Scholar
  53. Mane-Kapaj A, Kapajb I, Chan-Halbrendtc C, Totojanid O (2010) Assessing the comparative advantage of Albanian olive oil production. Int Food Agribusiness Manage Rev 13:1Google Scholar
  54. Marchini A, Diotallevi F, Fioriti L, Pampanini R (2010) A quantitative analysis of olive oil market in the North-West Italy. Enometrics XVII, PalermoGoogle Scholar
  55. Martínez MG, Aragonés Z, Poole N (2002) A repositioning strategy for olive oil in the UK market. Agribusiness 18(2):163–180View ArticleGoogle Scholar
  56. McEwan JA (1994) Consumer attitudes and olive oil acceptance: the potential consumer. Grasas y aceites 45(1–2):9–15View ArticleGoogle Scholar
  57. Menapace L, Colson G, Grebitus C, Facendola M (2008) Consumer preferences for extra virgin olive oil with country-of-origin and geographical indication labels in Canada. In: American Agricultural economics Association Annual MeetingGoogle Scholar
  58. Menapace L, Colson G, Grebitus C, Facendola M (2011) Consumers’ preferences for geographical origin labels: evidence from the Canadian olive oil market. In: European Review of Agricultural Economics:jbq051Google Scholar
  59. Mili S (2006) Market dynamics and policy reforms in the EU olive oil industry: an exploratory assessment. In: Proceedings of the 98th EAAE Seminar “Marketing Dynamics Within the Global Trading System: New perspectives,” Chania, GreeceGoogle Scholar
  60. Mili S, Zúñiga MR (2001) Exploring future developments in international olive oil trade and marketing: a Spanish perspective. Agribusiness 17(3):397–415View ArticleGoogle Scholar
  61. Moher D, Liberati A, Tetzlaff J, Altman DG (2009) Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. Ann Intern Med 151(4):264–269View ArticleGoogle Scholar
  62. Monteleone E, Carlucci A, Caporale G, Wakeling I (1997) Analisi della preferenza dei consumatori per l’olio extra vergine di oliva. Rivista Italiana delle Sostanze Grasse 74(9):415–421Google Scholar
  63. Morales MT, Rios JJ, Aparicio R (1997) Changes in the volatile composition of virgin olive oil during oxidation: flavors and off-flavors. J Agric Food Chem 45(7):2666–2673View ArticleGoogle Scholar
  64. Mtimet N, Kashiwagi AK, Zaibet L, Masakazu N (2008) Exploring Japanese olive oil consumer behavior. In: 12th EAAE Congress ‘People, Food and Environments: Global Trends and European Strategies’, Gent (Belgium)., pp 26–29Google Scholar
  65. Mtimet N, Ujiie K, Kashiwagi K, Zaibet L, Nagaki M (2011) The effects of Information and Country of Origin on Japanese Olive Oil Consumer Selection. In: 2011 International Congress, August 30-September 2, 2011. European Association of Agricultural Economists, Zurich, SwitzerlandGoogle Scholar
  66. Mtimet N, Zaibet L, Zairi C, Hzami H (2013) Marketing olive oil products in the Tunisian local market: the importance of quality attributes and consumers’ behavior. J Int Food Agribusiness Mark 25(2):134–145View ArticleGoogle Scholar
  67. Nakano K, Kubo H, Matsumura S, Saito T, Fushiki T (2013) Effects of aroma components from oxidized olive Oil on preference. Biosci Biotechnol Biochem 77(6):1166–1170View ArticleGoogle Scholar
  68. Nelson JP, Kennedy PE (2009) The use (and abuse) of meta-analysis in environmental and natural resource economics: an assessment. Environ Resour Econ 42(3):345–377View ArticleGoogle Scholar
  69. Nielsen NA, Bech-Larsen T, Grunert KG (1998) Consumer purchase motives and product perceptions: a laddering study on vegetable oil in three countries. Food Qual Preference 9(6):455–466View ArticleGoogle Scholar
  70. Owen RW, Giacosa A, Hull WE, Haubner R, Würtele G, Spiegelhalder B, Bartsch H (2000) Olive-oil consumption and health: the possible role of antioxidants. Lancet Oncol 1(2):107–112View ArticleGoogle Scholar
  71. Pagliarini E, Bertuccioli M, Abba S (1994) Consumer attitudes and olive oil acceptance: the traditional consumer. Grasas y aceites 45(1–2):16–19View ArticleGoogle Scholar
  72. Piccolo D, Capecchi S, Iannario M, Corduas M (2013) Modelling consumer preferences for extra virgin olive oil: the italian case. In: Politica Agricola Internazionale/International Agricultural Policy., p 25Google Scholar
  73. Pupo D’Andrea MR (2007) Il mercato mondiale dell’olio d’oliva: attori, dinamiche, prospettive e bisogni di ricerca. In: AgriRegioniEuropa 10Google Scholar
  74. Recchia A, Monteleone E, Tuorila H (2012) Responses to extra virgin olive oils in consumers with varying commitment to oils. Food Qual Preference 24(1):153–161View ArticleGoogle Scholar
  75. Ribeiro JC, Santos JF (2005) Portuguese olive oil and the price of regional products: does designation of origin really matter? Tékhne Polytechnical Stud Rev 2(3):61–76Google Scholar
  76. Rothstein HR, Sutton AJ, Borenstein M (2005) Publication Bias in Meta-Analysis. In: Rothstein HR, Sutton AJ, Borenstein M (eds) Publication Bias in Meta-Analysis: Prevention, Assessment and Adjustments. John Wiley & Sons, Ltd, Chichester, UKView ArticleGoogle Scholar
  77. Sandalidou E, Baourakis G, Siskos Y (2002) Customers’ perspectives on the quality of organic olive oil in Greece: a satisfaction evaluation approach. Br Food J 104(3/4/5):391–406View ArticleGoogle Scholar
  78. Santosa M, Guinard J-X (2011) Means-end chains analysis of extra virgin olive oil purchase and consumption behavior. Food Qual Preference 22(3):304–316View ArticleGoogle Scholar
  79. Santosa M, Abdi H, Guinard J-X (2010) A modified sorting task to investigate consumer perceptions of extra virgin olive oils. Food Qual Preference 21(7):881–892View ArticleGoogle Scholar
  80. Scarpa R, Del Giudice T (2004) Market segmentation via mixed logit: extra-virgin olive oil in urban Italy. J Agric Food Ind Organ 2:1Google Scholar
  81. Scarpa R, Philippidis G, Spalatro F (2005) Product‐country images and preference heterogeneity for Mediterranean food products: a discrete choice framework. Agribusiness 21(3):329–349View ArticleGoogle Scholar
  82. Sillani S, Esposito A, Del Giudice T, Caracciolo F (2014) Le preferenze dei consumatori della provincia di Trieste per l’olio extra vergine di oliva d’alta gamma. Economia Agro-alimentare 1:139–155Google Scholar
  83. Simpson RJS, Pearson K (1904) Report on certain enteric fever inoculation statistics. Br Med J 2(2288):1243–1246Google Scholar
  84. Soler F, Gil JM, Sanchez M (2002) Consumers’ acceptability of organic food in Spain: results from an experimental auction market. Br Food J 104(8):670–687View ArticleGoogle Scholar
  85. Thompson SG, Sharp SJ (1999) Explaining heterogeneity in meta‐analysis: a comparison of methods. Stat Med 18(20):2693–2708View ArticleGoogle Scholar
  86. Tsakiridou E, Mattas K, Tzimitra-Kalogianni I (2006) The influence of consumer characteristics and attitudes on the demand for organic olive oil. J Int Food Agribusiness Mark 18(3–4):23–31View ArticleGoogle Scholar
  87. Van der Lans IA, Van Ittersum K, De Cicco A, Loseby M (2001) The role of the region of origin and EU certificates of origin in consumer evaluation of food products. Eur Rev Agric Econ 28(4):451–477View ArticleGoogle Scholar
  88. Vlontzos G, Duquenne MN (2014) Assess the impact of subjective norms of consumers’ behaviour in the Greek olive oil market. J Retailing Consum Serv 21(2):148–157View ArticleGoogle Scholar
  89. Ward RW, Briz J, de Felipe I (2003) Competing supplies of olive oil in the German market: an application of multinomial logit models. Agribusiness 19(3):393–406View ArticleGoogle Scholar
  90. Yangui A, Costa Font M, Gil JM (2013) The effect of food related personality traits and lifestyle orientation on consumer’s behavior related to extra virgin olive oil: estimation of an extended hybrid choice model. In: 4th International Conference of the African Association of Agricultural Economists, September 22–25, 2013, Hammamet, TunisiaGoogle Scholar
  91. Yangui A, Akaichi F, Costa-Font M, Gil JM (2014a) Are ranking preferences information methods comparable with the choice experiment information in predicting actual behavior? In: 2014 International Congress, August 26–29, 2014. European Association of Agricultural Economists, Ljubljana, SloveniaGoogle Scholar
  92. Yangui A, Costa-Font M, Gil JM (2014b) Revealing additional preference heterogeneity with an extended random parameter logit model: the case of extra virgin olive oil. Spanish J Agric Res 12(3):553–567View ArticleGoogle Scholar
  93. Zanoli R, Gambelli D, Naspetti S (2002) Il posizionamento dei prodotti tipici e biologici di origine italiana: un’analisi su 5 Paesi. Rivista di Economia Agraria 58(4):477–509Google Scholar

Copyright

© Del Giudice et al. 2015

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.