Understanding Society User Support

Please provide more detail - ground rules can be found here: https://www.understandingsociety.ac.uk/support/projects/support/wiki
Jakob

So, details:
- I am using Stata
- I considered from wave "i" to wave "r".
- I renamed all the variables in the waves, so that the name was always the same.
- I generated a new variable, "wave", which tell associates each obs to a wave.
- I used command "append" to merge all the dataset from wave "i" to wave "r", keeping only the variables I need (including PID).

sorting by "PID" and wave, I expect to have vertically the first PID observed for wave i,j,k,l,m,n,o,p,q,r; then, the second PID for all the waves and so on. Because of attrition, it might be that after some time there are no more observation (something like i, j,k.) Instead, for some PID I have : i,j,l (k missing).

For instance for pid "10014578" I have all the waves,except k (2001).

1. In the BHPS respondents are eligible for interview even if they have not responded in one wave. As a result different response patters are observed including the ones you pointed out. Some people may respond for a few waves and then not respond every again, while others respond intermittently, yet others respond in all waves.

2. There is no concept of a longitudinal household in the BHPS and so household IDs are not unique across waves - these are unique within a wave across different data files. So, the same person living in a single person household may have two different hid in two waves.