diff_diff.compute_sample_size#

diff_diff.compute_sample_size(effect_size, sigma, power=0.8, alpha=0.05, n_pre=1, n_post=1, rho=0.0, treat_frac=0.5, deff=1.0)[source]

Convenience function to compute required sample size.

Parameters:

  • effect_size (float) – Treatment effect to detect.

  • sigma (float) – Residual standard deviation.

  • power (float, default=0.80) – Target statistical power.

  • alpha (float, default=0.05) – Significance level.

  • n_pre (int, default=1) – Number of pre-treatment periods.

  • n_post (int, default=1) – Number of post-treatment periods.

  • rho (float, default=0.0) – Within-unit (serial) equicorrelation for panel designs. Higher rho LOWERS the MDE (Burlig et al. 2020, Eq. 2, equicorrelated case); valid range [-1/(T-1), 1).

  • treat_frac (float, default=0.5) – Fraction assigned to treatment.

  • deff (float, default=1.0) – Survey design effect (variance inflation factor).

Returns:

Required total sample size.

Return type:

int

Examples

>>> n = compute_sample_size(effect_size=5.0, sigma=10.0)
>>> print(f"Required N: {n}")