Understanding Society User Support

Hello,

I need to link individual level data on individuals aged 16-20 with their mother's data in the BHPS. My original objective is to obtain information on whether their mother worked when they were 14. For this, I have used the variables maju, maju_bh and manssec8_dv. However, even after accounting for the fact that these questions were only asked to new entrants in the survey, there are many missing values remaining.

As an alternative, I an now planning to link individual observations with their mother's data from the indresp datafiles using the mnpid_bh linking variable. However, the problem that arises now is as follows: mnpid_bh gives the PID of the biological mother, instead of the PIDP. On the other hand, the BHPS indresp datafiles only contain the harmonised PIDP, and not the PID that was used in BHPS. The PID only appears when we append the BHPS with the UKHLS, in which case the PID is given only for those for those who appeared in both the BHPS as well as the UKHLS. For those who appeared only in the BHPS, I have only the PIDP and not the PID, and I cannot use the variable mnpid_bh to do the linking.

My question is: is there any other datafile where the PID of all BHPS respondents is available (even those who did not carry over to the UKHLS)?