Map which contrasts are estimable, and on what evidence, across target means

Estimability of the average conditional link-scale contrast is a function of the target means. A contrast identified at the covariate origin need not be identified where the relevant component by effect-modifier interactions are not pinned down. This plot evaluates estimable_effects_at() over a grid and tiles the result, separating contrasts identified by IPD (a within-study interaction, which randomization protects) from those identified only ecologically, from between-study differences in aggregate covariate means (which randomization does not protect; Berlin et al. 2002).

Usage

plot_estimability(object, em, values, at = NULL, reference = NULL, ...)

Arguments

object

A cmlnmr() fit.

em

Name of the effect modifier to vary across the grid.

values

Numeric vector of target values for em.

at

Optional named vector fixing the other effect modifiers. Defaults to 0 for each.

reference

Reference treatment. Defaults to the fit's reference.

...

Unused.

Value

A ggplot object.

Details

There is no counterpart in multinma.

References

Berlin JA, Santanna J, Schmid CH, Szczech LA, Feldman HI (2002). Individual patient- versus group-level data meta-regressions for the investigation of treatment effect modifiers. Statistics in Medicine, 21(3), 371–387.

See also

estimable_effects_at(), plot_rank_curve()

Examples

if (FALSE) {
plot_estimability(fit, em = "x1", values = seq(-1, 1, by = 0.5))
}