About this Session

In this session you will learn about the logic of quasi-experimentation. We will focus on designs with and without comparison groups.

Preparing for Class

  • SCC Chapters 4 and 5
  • Cluver, L., Meinck, F., Yakubovich, A., Doubt, J., Redfern, A., Ward, C., … & Romero, R. H. (2016). Reducing child abuse amongst adolescents in low-and middle-income countries: a pre-post trial in South Africa. BMC Public Health, 16(1), 567.
  • McKinnon, B., Harper, S., Kaufman, J. S., & Bergevin, Y. (2014). Removing user fees for facility-based delivery services: a difference-in-differences evaluation from ten sub-Saharan African countries. Health Policy and Planning, czu027.
  • Review the application activity that we will complete in class
  • Pre-class readiness assessment


Posted here after class

In-Class Activity

A. Pre-Post Parenting Trial in South Africa

Cluver et al. (2016) report on a child abuse prevention program conducted in South Africa. Use what you’ve learned so far to identify the key details about the research design and methods. Pay particular attention to the limitations of this study design.

B. Causal Inference in the Time of Cholera

This activity was designed by Amy Finnegan (with credit due to Mastering Metrics). I probably made it less cool with my edits over time.

Difference-in-difference analysis is quite literally one of the oldest tricks in the book. In the mid-1800s, John Snow used this method to discover how residents of London were being infected with cholera.

Snow observed that the Southwark and Vauxhall Company and the Lambeth Company supplied water to high-death-rate districts in South London. Both companies used the Thames—which was highly contaminated—as their water source before 1852. In 1852, the Lambeth Company began to source water from the Thames Ditton river—which was upstream and uncontaminated. Snow was able to show that between 1849 and 1854, districts that remained supplied by the Southwark and Vauxhall Company saw an increase in deaths from cholera while those supplied by the Lambeth Company experienced a reduction in deaths from cholera.

Eve and Eric visit the pump:

Use the table here taken from Snow’s original 1855 article to reproduce Snow’s difference-in-difference estimates.


The objectives of this activity are as follows:

  • to generate various quasi-experimental estimates of causal effect and evaluate how they change as the evaluation strategy becomes more rigorous
  • to assess threats to validity in quasi-experimental difference-in-difference designs; and
  • to produce graphical representations of results.

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