Detect Global Pre-Loop Imputation (Leakage Check)

Checks whether a feature matrix has already been imputed (no NAs remaining) when NAs are expected. Call this at the top of a CV loop to detect accidental global imputation.

Usage

check_no_premature_imputation(X, expected_na_rate = 0, label = "X")

Arguments

X

Feature matrix to check

expected_na_rate

Expected proportion of NAs (0 to 1). If the matrix has fewer NAs than expected, a warning is issued.

label

Label for the matrix in warning messages (e.g., "panel_mat")

Value

Invisible TRUE if check passes, FALSE with warning if suspicious