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Ingredients

Ingredients.Rmd

At each look, the function batss.glm defines a number of ingredients or derived quantities which can be used as inputs to the user-defined functions specified in arguments eff.arm, fut.arm, eff.trial, fut.trial, and RAR to perform adaptations. This document describes each ingredient.

n

  • object type: a vector of integers of the same length and order as argument prob0.

  • description: n provides the number of participants that have completed follow up in each treatment arm at the look of interest. This includes control and intervention arms, both active and dropped (inactive). sum(n) therefore corresponds to the total number of participants that have completed follow-up to-date in the trial.

m

  • object type: an integer scalar.

  • description: m corresponds to the number of participants to be randomised to the different groups (including control) at a given look. It is therefore needed in RAR and group allocation functions .

N

  • object type: an integer scalar.

  • description: N corresponds to the maximum sample size of the trial as specified in argument N of batss.glm.

posterior

Depending on the context - efficacy, futility or RAR - posterior corresponds to (possibly) different probabilities and takes different lengths.

  • Efficacy-related ingredient
    • object type: a numerical scalar.
    • description: in this context, posterior corresponds to the (posterior) probability of the target parameter being greater or smaller (depending on the argument 'alternative' of [batss.glm]) than ‘delta.eff’.
  • Futility-related ingredient
    • object type: a numerical scalar.
    • description: in this context, posterior corresponds to the (posterior) probability of the target parameter being greater or smaller (depending on the argument 'alternative' of [batss.glm]) than ‘delta.fut’.
  • RAR-related ingredient
    • object type: a numerical vector of length ‘number of active target parameters’ at a given look.
    • description: in this context, posterior corresponds to the vector of (posterior) probabilities of the active target parameters being greater or smaller (depending on the argument 'alternative' of [batss.glm]) than ‘delta.RAR’.

active

  • object type: vector of the same length and order as 'prob0'.

  • description: active indicates if the different arms (including the control group) are active (TRUE) or not (FALSE) at the look of interest.

ref

  • object type: a vector of the same length and order as 'prob0'.

  • description: ref indicates which group is the reference one (TRUE). It is typically the first one as the reference group is typically not dropped and has position 1 in 'prob0'.

prob

  • object type: a named numerical vector of length ‘number of active arms (including the reference group)’.

  • description: prob is the output of the under-defined function provided in ‘RAR’ and and is used in defining the vector of allocation ratios or probabilities for all active arms (including the reference group). Note that, if RAR = NULL, prob equals prob0 (with appropriate subsetting for arms that have been dropped).

eff.target

  • object type: a vector of the same length as argument which (i.e., the number of target parameters)

  • description: eff.target indicates if efficacy was reached for each target parameter at the stage of interest or before.

fut.target

  • object type: a vector of the same length as argument which (i.e., the number of target parameters)

  • description: fut.target indicates if futility was declared for each target parameter at the stage of interest or before.