Adjust for Selection Bias in Web Surveys with Propensity Scores: The case of the Health and Retirement Study

Many web surveys allow respondents to self
select into the survey. Making inference about the
population from a self-selected survey is very
difficult. We analyzed data from the Health and
Retirement Study (HRS) respondents of the 2002
wave as well as supplementary information about
which subset of HRS respondents also responded
to an additional web survey (web responders).
The HRS is a longitudinal study of health,
retirement and aging. The target population of the
HRS includes all adults in the contiguous United
States, aged 51 and over, who reside in
households. We investigated whether it is
possible to adjust for selection bias using
propensity scores. We found that it is possible to
make inferences for financial assets based on data
from web responders only. However, making
inferences about home values was not possible
based on data from the web responders only.