Biased Coin Design Allocation

Description

Allocates observations sequentially using a biased coin design. If equal numbers have been allocated to treatment and control, the next observation is allocated to treatment with probability 1/2. If there are more units assigned to treatment than control, the next observation is allocated to control with probability p; if there are more units assigned to control than treatment, the next observation is allocated to treatment with probability p.

Usage

1
bcdalloc(n, pbcd, tol = 1e-06)

Arguments

n

number of observations

pbcd

probability p used for biased coin

tol

tolerance used for allocation

Value

Vector of zeroes and ones indicating the allocation of each unit to treatment (1) or control (0)

Author(s)

Xiaoshu Zhu xiaoshuzhu@westat.com and Sharon Lohr

References

Efron, B. (1971). Forcing a sequential experiment to be balanced. Biometrika, 58(3), 403-417.

Lohr, S. and X. Zhu (2015). Randomized Sequential Individual Assignment in Social Experiments: Evaluating the Design Options Prospectively. Sociological Methods and Research. [Advance online publication: December 27, 2015] doi: 10.1177/0049124115621332.

Examples

1
bcdalloc(20,0.7)