Difference-in-differences

Difference-in-differences is a statistical method used to evaluate the effect of a specific change or policy by comparing outcomes over time between a group affected by the change and a similar group not affected. It helps isolate the impact of the change by accounting for general trends that would have occurred anyway. Essentially, it looks at how much the outcome changes in the treated group relative to the control group before and after the intervention, allowing us to estimate the true effect of the change accurately.