optimal_proportion {preference}

Unstratified Optimized Theta

Description

Calculates the optimal proportion of patients assigned to the choice arm in an unstratified two-stage randomized trial

Usage

optimal_proportion(w_sel, w_pref, w_treat, sigma2, phi, delta_pi, delta_nu)

Arguments

w_sel

weight assigned to the estimation of the selection effect. Each weight should be a numeric value between 0 and 1 and sum of three weights should be 1.

w_pref

weight assigned to the estimation of the preference effect. Each weight should be a numeric value between 0 and 1 and sum of three weights should be 1.

w_treat

weight assigned to estimation of the treatment effect. Each weight should be a numeric value between 0 and 1 and sum of three weights should be 1.

sigma2

variance estimate. Should be a positive numeric value.

phi

proportion of patients preferring treatment 1. Should be numeric value between 0 and 1.

delta_pi

overall study preference effect.

delta_nu

overall study selection effect.

References

Walter et. al. (2011). "Optimal allocation of participants for the estimation of selection, preference and treatment effects in the two-stage randomised trial design." Stat Med, 31(13):1307-1322. (PubMed)

Examples

optimal_proportion(w_sel=0.2, w_pref=0.4, w_treat=0.4, sigma2=1, phi=0.5,
                   delta_pi=1, delta_nu=0.5)