Table 1 Comparison of research methodology options

Self-reporting by retail companies

Cost-effective

It can provide an analysis of a period, not just a snapshot

Pilot study revealed a sporadic response from retailers, and the data quality was low

Data resolution is likely low to middle level (no individual articles)

No method for the validation of data

Incoherent comprehension and data structure

Tracking of sales with cash register data

Cost-effective after an initial technical implementation phase

It would provide high resolution of data

Able to provide a constant data flow instead of a snapshot

Computer-based method for validation is possible (even interlinkages with other databases are possible, such as tax reports, accounting, and supply analytics)

Bar codes (and the product information behind them) are often not related to the place of origin, and linkages are difficult to make

Only able to report on sales and not on the physical assortment

Substantial development in the data structure would be needed with an (international) collaboration of retailers and suppliers, which is unrealistic at present

Physical inspection of the assortment

Method for validation (photo documentation)

Provides high-resolution data

Proof-of-concept (previous experience)

Labour-intensive

Needs trained staff

Provides a snapshot instead of the analysis of a period or a constant data flow