ABLFL = Y, then BASE must equal AVAL - need more understanding

Hello support team -

I did ADAM BDS datasets fro questionarie datsets - here is need of analysis is

1. we have two types of questionarie - 1). Pre questions and 2). post questions.

2. we are intreatsed see PRE vs POST.

3. so here BASE and AVAL wonot be same.

Could you please let me know your thoughts and I appreciate your swift help.

Thanks,

Venkata