In my semester project I have made 2 different surveys. The first was send out in the beginning of April, and the other yesterday.

I would like to compare my results both internally in the surveys, which does not seem to be that big of a problem, but also between them, which gives me quite the headache.

The problem is that some of the respondents in survey 2 have also answered the first survey. I know this because there is a question in survey 2 asking whether or not the respondent have answered the first one as well, which some have, and some have not.

In the second survey I know which of the respondents have answered the first one as well, but I have no way of determining which of the respondents in the first survey also answered the second survey.

This means that I have no idea of how to compare the surveys statistically. I have looked at comparing the surveys with a mixed design, but I am not sure if this will work, due to the fact that between the surveys some respondents are within and some are between.

All the data I have to analyze statistically is interval data, and if it meets the assumptions I'm going to use paired t-test for some of the questions, and ANOVA for the rest, for the analysis within each of the surveys.

I haven't gathered all my data from the second survey, yet.

I really hope someone can help me.

Regards

Cecilie