Sample sizes nurse visit & blood samples
Dear Understanding Society team,
My colleague and I have recently started working with the nurse and biomarker data from waves 2 and 3, bu have come across an inconsistency in the documentation regarding the sample.
In the document entitled "Waves 2 and 3 Nurse Health Assessment, 2010-2012", the eligible sample sizes (+ reasons for non-eligibility) are given on pages 9 and 10 for the GPS and BHPS components separately. At the end of the flow chart we see that the blood sample was taken from 10,175 respondents in wave 2 and 3,342 in wave 3. The total should therefore be 20,644.
However, in the document "Biomarker User Guide and Glossary" a table of combined sample/ response is provided on page 12. Here the number participating in the nurse visit is 20,700. Note that there are further mismatches in other categories (e.g. no contact, pregnant, ill, died or out of scope).
(This second document also provides the reason for the difference in sample size between the health assessment and blood sample so is useful to us).
Could you clarify which source we should follow, or how we might be able to reconcile these differences?
With best wishes,