Search function for scaled logit protection covariate levels

The search engine behind get_protection_level. Should not usually be necessary to call this directly.

find_prot_titre_val(
  fit,
  var_name,
  newdata = NULL,
  prot_var_name = "prot_point",
  lvl = 0.5,
  ci_level = 0.95,
  tol = 10^(-7)
)

Arguments

fit	Object returned by `sclr`.
var_name	Name of the covariate for which the protection values should be calculated. This name should appear in the formula of the call to `sclr` which was used to generate `fit`.
newdata	A dataframe with all covariates except the one for which protection values should be calculated.
prot_var_name	A variable name among those returned by `predict.sclr` which needs to equal `lvl` at the value of `var_name` that is supposed to be found.
lvl	Protection level to find titre values for. Default is 0.5 (50%).
ci_level	Confidence level for the calculated interval. Default is 0.95.
tol	Tolerance. The values will be found numerically, once the algorithm converges within `tol` of `lvl` it stops looking. Default is \(10^(-7)\).

A dataframe. Will have the same variables as newdata with the addition of the var_name variable.