Here's what she looked at:
- Social marginalization and its effects on participant attrition in a particular study population
- The relationship between marginalization and health, where she found a negative association between severe marginalization and health
- Whether attrition of hard-to-find participants affects results, where she found that it can
The latter part of the dissertation worked by taking a set of results from a particular study population, backing out hard-to-find respondents, and re-running the original analysis. There were differences in the results. Retaining hard-to-find respondents has a significant effect on research results, in other words, and thus, possibly, on policy based on those results. She did an enormous amount of work on hard-to-find survey respondents and the efforts that went into retaining them in the study population, because the original researchers went to incredible lengths to retain as many respondents as possible.
I'm so proud of her!!