multilevelMatching (version 1.0.0)

calcKMVarFactor: Calculate the variance component for number of times unit is a match.

Description

This function calculates K_M_var_factor, a numeric vector. Each entry in this vector is a function of the number of times each unit is matched to, aka \(K_M(i)\) (corresponding to Kiw, where \(M\) corresponds to M_matches. The calculation in this function comes from Theorem 7, page 251 of Abadie and Imbens (2006) Econometrica. The K_M_var_factor is an important component in the variance estimation, created in the function estVarAI2006 in estimateTau.

Usage

calcKMVarFactor(Kiw, M_matches)

Arguments

Kiw

A vector of times each unit is matched to

M_matches

Number of matches per unit for imputing potential outcomes, as in Abadie and Imbens (2006).

Value

A numeric vector.

This function is exported for use in other packages.

References

Abadie, A., & Imbens, G. W. (2006). Large sample properties of matching estimators for average treatment effects. econometrica, 74(1), 235-267. https://doi.org/10.1111/j.1468-0262.2006.00655.x

Examples

# NOT RUN {
   calcKMVarFactor(Kiw = 2, M_matches = 4)

# }