Résumé
We use Almost Ideal Demand Systems (AIDS) models estimated by the nonlinear seemingly unrelated regression (SUR) method on scanner data (i) to examine the demand for ecolabeled food products (organic and fair trade) as a function of the good having a private label (PL) or a national brand (NB) and (ii) to assess the impact of information campaigns promoting organic and fair trade products. We find that while demand is elastic for NB organic milk and NB fair trade coffee, it is inelastic for their PL counterpart. As for organic eggs, demand is always inelastic. Cross-price elasticities show substitutability between ecolabeled and conventional goods but only within the NB goods (milk and eggs) and within the PL goods (milk and coffee), but also complementarity between NB conventional and PL ecolabeled goods (milk and coffee). Finally, we find that while information campaigns increase the predicted expenditure shares of PL organic milk by 33%, of NB fair trade coffee by 50%, they decrease the predicted expenditure shares of PL conventional eggs but only by 3%. These effects are non-lasting.