Regression Discontinuity - Institute for Policy Research
Regression Discontinuity - Institute for Policy Research
Regression Discontinuity - Institute for Policy Research
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Variance of Impact Estimator in RA<br />
^<br />
Var ra (α 0 ) = σ 2 (1-R ra2 )<br />
np(1-p)(1-ns-co) 2<br />
• σ 2 is the variance of mean student outcomes across schools<br />
within the treatment or comparison group<br />
• R ra<br />
2<br />
is the square of the correlation between school<br />
outcomes and the assignment variable<br />
• np(1-p) is the total variation in treatment status across<br />
schools<br />
• ns is the no-show (via appeals) rate<br />
• co is the cross-over (via participation) rate