Journal #J-05/2001
Aggregation over different qualities: Are there generic commodities?
Frank Asche(1), Atle Guttormsen & Sigbjørn Tveterås(2)
Department of Economics & Social Sciences Agricultural University of Norway PO Box 5033, N-1432 Ås, Norway http://www.nlh.no/ior/ e-mail: atle.guttormsen@ior.nlh.no

(1) Frank Asche, Centre of Fishery Economics, Norwegian School of Business Administration and Stavanger University College,
e-mail: frank.asche@tn.his.no

(2) Sigbjørn Tveterås, Centre of Fishery Economics, Norwegian School of Business Administration,
e-mail: sigbjorn.tveteras@tn.his.no

Asche, F., A. Guttormsen & S. Tveterås, (2001): "Aggregation over different qualities: Are there generic commodities?", Economics Bulletin, 3(13):1-6.

Abstract:
Aggregation over goods is always an issue in empirical analysis. However, while the problem of aggregation over different goods often is analysed, little attention has been given to the properties of generic goods such as e.g. coffee, wheat and salmon. Often these generic commodities contain a number of different qualities. In this paper a test for aggregation based on Lewbel s Generalized Composite Commodity Theorem (GCCT) using only price data is used to validate aggregation. We show by using price series for different weight-classes of salmon that the generic term salmon can be used for these products.

Key words: Aggregation, generic goods, Generalized Composite Commodity Theorem

To order: fax (+47) 6494 3012 or e-mail: ior@ior.nlh.no