Difference In Differences
4 articles
Using difference-in-differences in practice
When difference-in-differences is the right tool, the three assumptions stated as decisions, and the ways it breaks, each shown in a worked Too Early To Say case with open code.
When the parallel-trends test fails on one lead, what's left?
Replicating Wang et al. (2026) TWFE-DiD on SNAP BBCE adoption from IPUMS ACS, with Goodman-Bacon decomposition and leave-one-out diagnostics.
Cycling Through Bad Ideas Faster: A Worked Example
How AI-augmented iterative critique compresses the cost of discarding bad ideas in applied research, illustrated through three coding rules, a controls…
Understanding the Limits of Parallel Trends Tests
Why a high p-value on a parallel-trends test can mislead, and how Rambachan-Roth sensitivity bounds reveal when a difference-in-differences claim is fragile.