# Determine operating characteristics of a randomised clinical trial design that assumes a Bernoulli distributed primary outcome variable

Source: `R/opchar.R`
`opchar.Rd`

`opchar` determines the operating characteristics (analytically) of a design returned by `des_one_stage` or `des_two_stage`, under given response rate scenarios (see `pi`).

    opchar(
      des = ph2rand::des_one_stage(),
      pi = des$opchar[, 1:2],
      k = 1:des$J,
      summary = FALSE
    )

## Arguments

des | An object of class `ph2rand_des`, as returned by `des_one_stage` or `des_two_stage`. Defaults to `ph2rand::des_one_stage()`.
pi | A `numeric` `vector` with two elements, or a `numeric` `matrix` or `data.frame` with two columns, giving the response rate scenarios to consider. The first element/column should correspond to the control arm and the second element/column to the experimental arm. Defaults to `des$opchar[, 1:2]`.
k | A `numeric` `vector` indicating which stages to consider in determining the operating characteristics. That is, it will condition the calculations on the trial ending in the stages given in `k`. Defaults to `1:des$J` (i.e., to all stages of the given design).
summary | A `logical` variable indicating whether a summary of the function's progress should be printed to the console. Defaults to `FALSE`.

## Value

A `list` with additional class `"ph2rand_opchar"`, containing each of the input parameters along with a tibble in the slot `$opchar`, which gives the determined operating characteristics.

## See also

`des_one_stage`, `des_two_stage`.

## Examples

    # The default two-stage design
    des    <- des_two_stage()
    # Its operating characteristics under the uninteresting and interesting
    # scenarios
    opchar <- opchar(des)
    # The same operating characteristics, conditioning on the trial ending in
    # stage 2
    opchar <- opchar(des, k = 2)