Hello everyone;

I am working with the National Longitudinal Survey of Children and Youth (NLSCY); a study conducted every 2 years. There are 8 reference periods, each named Cycle 1, Cycle 2, Cycle 3,...... Cycle 8.

I am looking at the impact of participation in regulated childcare (daycare or licensed family-care center) on the school readiness of low-income children. School-readiness is measured using a test score called PPVT-R.

My dependent variable is the standard score of PPVT-R which is administered once to children aged 4-5 across all cycles. My dependent variable is participation in regulated childcare. I am looking at the effects of school-readiness prior to Quebec's subsidized daycare (2000) and after, and comparing it to Ontario.

I would need to pool Cycles 1, 2 and 3 together, and Cycles 4,5,6,7,8, together so that I have information on the child's childcare arrangements. If I do not do this, 4-5 years either (a) dont have information on childcare because they are in school, or (b) their childcare is not relevant.

Therefore, I want to know if there is a way to pool the variables from participants across all cycles.

Example: Child who is aged 3 in Cycle 2 has information on childcare arrangements (eg: attends daycare). At Cycle 3 they are 5 and took the PPVT-R (childcare arrangement is not applicable or changed since they are in Kindergarten). I would need to use the observation of the childcare variable off Cycle 2 instead of cycle 3 so that my regression analysis will make sense.

The PERSUK variable is the child's unique identifier; each child is given a unique number that is the same across cycles. I am guessing I merge 1:1 using PERSUK?

If there isnt enough information in this i am sorry. i also emailed Statistics Canada for help just thought I would also try here.