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.

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.

Guidance is given on designing SP experiments. A good design will result by trial and error from gradual amendment of earlier drafts. Allowance must be made for variations in taste, for example in valuations of time and cost.