Bill -- Sounds like one of your problems is with the form of the questionnaire. Instead of having a paper and pencil questionnaire, have you thought about using an interviewer-administered one? Although the up-front costs are higher (you have to hire interviewers), the data quality is also better, since you can insure random selection and need fewer interviews. BTW, most self-administered interviewing situations do not produce random samples. Even if visitors are selected at random participants tend to be self-selected. The big problem is in determining the extent of the bias due to self-selection. At least with the interviewer administered study you can measure the extent of bias (through a logistic regression on the probability of refusal) and adjust your sample accordingly. These may not help you with your Feb. study, but you might want to consider it. E-mail me privately if you want to see some examples. --Adam Adam Bickford, Smithsonian Institution, Institutional Studies Office:: [log in to unmask] (202) 786-2289