R: Posterior Draws of the Linear Predictor

posterior_linpred.brmsfit {brms} | R Documentation

## Posterior Draws of the Linear Predictor

### Description

Compute posterior draws of the linear predictor, that is draws before applying any link functions or other transformations. Can be performed for the data used to fit the model (posterior predictive checks) or for new data.

### Usage

    ## S3 method for class 'brmsfit'
    posterior_linpred(
      object,
      transform = FALSE,
      newdata = NULL,
      re_formula = NULL,
      re.form = NULL,
      resp = NULL,
      dpar = NULL,
      nlpar = NULL,
      incl_thres = NULL,
      ndraws = NULL,
      draw_ids = NULL,
      sort = FALSE,
      ...
    )

### Arguments

`object` | An object of class `brmsfit`.
`transform` | Logical; if `FALSE` (the default), draws of the linear predictor are returned. If `TRUE`, draws of transformed linear predictor, that is, after applying the link function are returned.
`newdata` | An optional data.frame for which to evaluate predictions. If `NULL` (default), the original data of the model is used. `NA` values within factors are interpreted as if all dummy variables of this factor are zero. This allows, for instance, to make predictions of the grand mean when using sum coding.
`re_formula` | formula containing group-level effects to be considered in the prediction. If `NULL` (default), include all group-level effects; if `NA`, include no group-level effects.
`re.form` | Alias of `re_formula`.
`resp` | Optional names of response variables. If specified, predictions are performed only for the specified response variables.
`dpar` | Name of a predicted distributional parameter for which draws are to be returned. By default, draws of the main distributional parameter(s) `"mu"` are returned.
`nlpar` | Optional name of a predicted non-linear parameter. If specified, expected predictions of this parameters are returned.
`incl_thres` | Logical; only relevant for ordinal models when `transform` is `FALSE`, and ignored otherwise. Shall the thresholds and category-specific effects be included in the linear predictor? For backwards compatibility, the default is to not include them.
`ndraws` | Positive integer indicating how many posterior draws should be used. If `NULL` (the default) all draws are used. Ignored if `draw_ids` is not `NULL`.
`draw_ids` | An integer vector specifying the posterior draws to be used. If `NULL` (the default), all draws are used.
`sort` | Logical. Only relevant for time series models. Indicating whether to return predicted values in the original order (`FALSE`; default) or in the order of the time series (`TRUE`).
`...` | Further arguments passed to `prepare_predictions` that control several aspects of data validation and prediction.

### See Also

`posterior_epred.brmsfit`

### Examples

    ## Not run:
    ## fit a model
    fit <- brm(rating ~ treat + period + carry + (1|subject),
               data = inhaler)

    ## extract linear predictor values
    pl <- posterior_linpred(fit)
    str(pl)

    ## End(Not run)

[Package brms version 2.16.3 Index]