computep {senstrat}

Computes individual and pairwise treatment assignment probabilities.

Description

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).

Usage

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.

Value

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.

Note

The function computep is called by the function ev.

Author(s)

Paul R. Rosenbaum

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.

Examples

computep(10,5,6,2)