External data borrowed through a power prior

Specifies external (historical) data for one group together with the power prior weight \(a_0\). The likelihood of the external data is raised to the power \(a_0\), so that \(a_0 = 0\) ignores the external data and \(a_0 = 1\) pools it with the current data. For the conjugate models used in this package the resulting posterior distribution has a closed form, so no Markov chain Monte Carlo sampling is needed.

Usage

borrow(data, a0)

Arguments

data: External data created by data_binary, data_continuous, data_binary2, data_continuous2 or data_tte.
a0: Power prior weight, a number from 0 to 1.

Value

An object of class "qdm_borrow" with elements data and a0.

Examples

borrow(data_binary(n = 20, y = 8), a0 = 0.5)
#> External data: binary, n = 20, y = 8, a0 = 0.5