prior function

Beta priors determination based on different prior information

Beta priors determination based on different prior information

The prior function to calculate the Beta prior parameters

prior(type, mu, v, N, W, init)

Arguments

  • type: type of prior information: "MeanVar" uses mean and variance, "Optimist" uses (ORR) mean, "ORRN" uses ORR and smaple size, "ORRW" uses ORR and CI width.
  • mu: prior(ORR) mean.
  • v: prior variance
  • N: prior sample size.
  • W: prior confidence interval width.
  • init: initial value to solve the nonlinear equations for "ORRW" type.

Returns

  • parameters: the vector of Beta parameters: aa and bb

Examples

prior(type = "MeanVar", mu=0.2, v=0.025) prior(type = "Optimist", mu = 0.2) prior(type = "ORRN", mu = 0.2, N = 10) prior(type = "ORRW", mu = 0.2, W = 0.5)

References

Thall, P. F., Simon, R. (1994). Practical Bayesian guidelines for phase IIB clinical trials. Biometrics 50 : 337-349.

Mayo, M. S., & Gajewski, B. J. (2004). Bayesian sample size calculations in phase II clinical trials using informative conjugate priors. Controlled clinical trials 25 (2): 157-167.

Tan, S. B., & Machin, D. (2002). Bayesian two-stage designs for phase II clinical trials. Statistics in medicine 21 (14): 1991-2012. New York: Wiley.