Heterogeneous products and tests for an appropriate aggregation level considering different qualities: evidence from fresh hake at Barcelonas wholesale market

This paper stresses the importance of considering an appropriate aggregation level for databases and demand analyses, as an inappropriate level may lead to biased estimates. This is illustrated by an analysis of different fresh hake products from Mercabarna, Barcelonas wholesale market. The literature on seafood demand regards hake as a single product species. Nevertheless, in the Spanish market, many types of fish, ranging from inferior to luxury goods, are marketed as hake. Our results were in accordance with empirical observations, and suggest the need for analysis at a greater depth than the species level. Thus, this questions the results of previous demand studies and most databases, which have not taken the appropriate product aggregation level into account.