Possible bug: error is thrown saying check_model is not implemented, …

…if model formula contains a ratio (#751)

DESCRIPTION

@@ -1,7 +1,7 @@
 Type: Package
 Package: performance
 Title: Assessment of Regression Models Performance
-Version: 0.12.0.10
+Version: 0.12.0.11
 Authors@R:
     c(person(given = "Daniel",
              family = "Lüdecke",

NEWS.md

@@ -27,6 +27,9 @@
   variable that was named like a valid R function name (e.g., `lm(log(lapply) ~ x)`,
   when data contained a variable named `lapply`).
 
+* Fixed issue in `check_predictions()` for linear models when response was
+  transformed as ratio (e.g. `lm(succes/trials ~ x)`).
+
 # performance 0.12.0
 
 ## Breaking

R/check_predictions.R

@@ -303,10 +303,18 @@ pp_check.lm <- function(object,
   pattern <- "^(scale|exp|expm1|log|log1p|log10|log2|sqrt)"
 
   # check for transformed response, and backtransform simulations
-  if (!is.null(resp_string) && grepl(paste0(pattern, "\\("), resp_string)) {
+  if (!is.null(resp_string) && length(resp_string) == 1 && grepl(paste0(pattern, "\\("), resp_string)) {
     out <- .backtransform_sims(out, resp_string)
   }
 
+  # sanity check - do we have a ratio or similar?
+  if (is.data.frame(response)) {
+    # get response data, evaluate formula
+    response <- eval(str2lang(insight::find_response(object)),
+      envir = insight::get_response(object)
+    )
+  }
+
   out$y <- response
 
   attr(out, "check_range") <- check_range

tests/testthat/test-check_predictions.R

@@ -128,3 +128,18 @@ test_that("check_predictions, glm, binomial", {
   expect_equal(head(out4$sim_1), c(0, 0, 0, 1, 0, 1), tolerance = 1e-4)
   expect_true(attributes(out4)$model_info$is_bernoulli)
 })
+
+
+test_that("check_predictions, lm, ratio-response", {
+  skip_if_not_installed("lme4")
+  data(cbpp, package = "lme4")
+  model1 <- lm(I(incidence / size) ~ period, data = cbpp)
+  set.seed(123)
+  out <- check_predictions(model1)
+  expect_equal(
+    head(out$y),
+    c(0.14286, 0.25, 0.44444, 0, 0.13636, 0.05556),
+    ignore_attr = TRUE,
+    tolerance = 1e-4
+  )
+})