Conjoint studies, appropriately designed and used, are found to be capable of predicting real behaviour in real markets. Discrete choice tasks are more reliable than ranking or rating tasks. The author makes suggestions for further research.

The error structure of SP models is a somewhat neglected topic. Utility functions from SP data cannot usually be used directly in demand forecasting. Market segment techniques should be used to deal with this till new techniques have been developed. More research is needed.

Revealed preference and stated preference data have traditionally been analysed by different methods. The authors show the value of SP. A combination of both methods would be a very useful framework for empirical studies.