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Check Convergence for a Regression Model

Source: R/check_convergence.R
check_convergence.Rd

Assesses model convergence and provides diagnostics for each exposure (in univariate mode) or for the full model (in multivariable mode), depending on the regression approach used.

Usage

check_convergence(
  data,
  exposures,
  outcome,
  approach = "logit",
  multivariate = FALSE
)

Arguments

data

A data frame containing the dataset.

exposures

A character vector of predictor variable names. If multivariate = FALSE, each exposure is assessed separately. If multivariate = TRUE, exposures are included together.

outcome

A character string specifying the outcome variable.

approach

A character string specifying the regression approach. One of: "logit", "log-binomial", "poisson", "robpoisson", or "negbin".

multivariate

Logical. If TRUE, checks convergence for a multivariable model; otherwise, performs checks for each univariate model.

Value

A data frame summarizing convergence diagnostics, including:

Exposure

Name of the exposure variable.

Model

The regression approach used.

Converged

TRUE if the model converged successfully; FALSE otherwise.

Max.prob

Maximum predicted probability or fitted value in the dataset.

Details

For robpoisson, predicted probabilities (fitted values) may exceed 1, which is acceptable when estimating risk ratios but should not be interpreted as actual probabilities.

This function is useful for identifying convergence issues, especially for "log-binomial" models, which often fail to converge .

See also

[identify_confounder()], [interaction_models()]

Examples

if (requireNamespace("gtregression", quietly = TRUE)) {
  data(data_PimaIndiansDiabetes, package = "gtregression")

  check_convergence(
    data = data_PimaIndiansDiabetes,
    exposures = c("age", "bmi"),
    outcome = "diabetes",
    approach = "logit"
  )

  check_convergence(
    data = data_PimaIndiansDiabetes,
    exposures = c("age", "bmi"),
    outcome = "diabetes",
    approach = "logit",
    multivariate = TRUE
  )
}
#> Warning: Model fitting failed for the selected approach
#>               Exposure Model Converged Max.prob.
#> multivariable       NA logit     FALSE        NA