Identify a research question of interest to you, the population of interest, and a study design you might use to examine the question.
Are the contraceptive use habits of Haitian women associated with their obstetric history? I would attempt to answer this question using a cross sectional design of reproductive age women.
Explain how you might incorporate a sampling strategy into the study design (you might, for example, use respondent-driven sampling to initiate a cohort study).
A sampling strategy to capture a representative sample of women in Haiti could employ probability sampling (systematic random sampling) using geographic locations (GPS or similar?) selected randomly. Within each community, women can be approached from households randomly selected based on their location from the geolocation such as the 2nd house located north. This approach would be useful for this question because there may be many differences between women in rural vs urban settings so selecting women from even small market centers may not capture those who live very rurally.
Briefly discuss possible logistical/practical advantages and disadvantages to this plan.
Advantages: Because addresses are not used consistently in Haiti, using geolocations is more precise. Because this approach doesn’t rely on use of community resources (health center, market, school) a wider range of women will be selected. The statistical conclusions drawn from data from this sample would be stronger because of the samples representativeness. The geography of Haiti is clear so the ‘list’ of locations from which to draw the sample is available.
Disadvantages: The terrain in the Haitian countryside may make it challenging to find the chosen household even using this technique. This approach is more expensive than recruiting from one location in the community.
Finally, discuss whether you think incorporating the sampling strategy might help
(1) reduce bias in the estimation of univariate quantities (such as disease prevalence) and
(2) reduce bias in the estimation of causal effects.
Both of these concerns would be attenuated with the use of probability sampling which aims to reduce biased estimation because of a biased sample.