computep function

Computes individual and pairwise treatment assignment probabilities.

Of limited interest to most users, the computep function plays an internal role in 2-sample and stratified sensitivity analyses. The computep function is equations (9) and (10), page 496, in Rosenbaum and Krieger (1990).

computep(bigN, n, m, g)

Arguments

• bigN: Total sample size in this stratum.
• n: Treated sample size in this stratum.
• m: The number of 1's in the vector u of unobserved covariates. Here, u has bigN-m 0's followed by m 1's.
• g: The sensitivity parameter $\Gamma$, where $\Gamma \ge 1$.

Returns

• p1: Equation (9), page 496, in Rosenbaum and Krieger (1990) evaluated with u[i]=1.

• p0: Equation (9), page 496, in Rosenbaum and Krieger (1990) evaluated with u[i]=0.

• p11: Equation (10), page 496, in Rosenbaum and Krieger (1990) evaluated with u[i]=1, u[j]=1.

• p10: Equation (10), page 496, in Rosenbaum and Krieger (1990) evaluated with u[i]=1, u[j]=0.

• p00: Equation (10), page 496, in Rosenbaum and Krieger (1990) evaluated with u[i]=0, u[j]=0.

References

Rosenbaum, P. R. and Krieger, A. M. (1990). Sensitivity of two-sample permutation inferences in observational studies. Journal of the American Statistical Association, 85, 493-498.

Rosenbaum, P. R. (2002). Observational Studies (2nd edition). New York: Springer. Section 4.6.

Author(s)

Paul R. Rosenbaum

Note

The function computep is called by the function ev.

Examples

computep(10,5,6,2)