Doing a retest-reliability. How do I connect the identity of people first to second time?

Question

I have do do a retest-reliability. Meaning I will give the same test to the same people two times. But I have to somehow connect their first and second attempt. I now just created an open question, where they can produce an identity code. This code will be the same one first and second time. But how do I connect the two codes in an statistical evaluation afterwards? I cant do this manually, when its a lot of people.
I hope you somehow get my question, my english is not to good.

Answer 1

This code will be the same one first and second time.

If you alread have a code (and the procedure works), fine :)

Should you have issues with that code, you may also consider using the mailing feature to register an email address in the first questionnaire, and send a personalized invitation (that takes care of the code) via email. More about that: Multi-Wave Surveys with Self-Recruited Respondents

Talking about your analysis: It depends a bit on your statistics software. Usually, you will have these steps:

1. Separate the data from wave 1 and wave 2
2. Rename the variables in order to have different variable names in both data sets (e.g. AB01 -> AB01a and AB01b)
3. merge the dataset, using the merge/join feature of your statistic software and the individual code