Quasi-Experiments and Natural Experiments

Quasi-Experiments
Natural Experiments
Lecture Notes

This course studies causal designs that draw credibility from timing, thresholds, policy rules, encouragements, shocks, or comparison units. These designs are common in product, policy, education, marketing, public-sector, and platform settings where randomized evidence is unavailable or incomplete.

The objective is to build design-first judgment. By the end of the course, a reader should be able to explain what source of variation identifies the effect, diagnose the key assumptions, distinguish pre-trend evidence from proof, reason about treatment timing and spillovers, and write a careful decision interpretation.

Difference-in-differences estimate comparison across specifications

Figure: DiD estimates across near-equivalent specifications, highlighting how design credibility is checked through specification comparisons (adapted from Lecture 01: Difference-in-Differences).

Lecture Sequence

01. Difference-in-Differences

This lecture connects Difference-in-Differences to timing, comparison groups, and design diagnostics that shape the causal interpretation.

02. Event Studies

This lecture develops Event Studies with examples that make assumptions, diagnostics, and interpretation visible.

04. Synthetic Control

This lecture studies synthetic control through donor-pool choice, pre-period fit, placebo checks, and decision interpretation.

05. Regression Discontinuity

This lecture frames Regression Discontinuity as a decision problem and asks what evidence can be trusted, challenged, and communicated.

06. Instrumental Variables

This lecture builds intuition for Instrumental Variables and ties the result to model choice, uncertainty, and action.

07. Encouragement Designs

This lecture applies Encouragement Designs with emphasis on diagnostics, tradeoffs, and evidence limits.

08. Interrupted Time Series

This lecture develops Interrupted Time Series as a practical pattern for analysis, diagnostics, and decision support.