Impute Missing Values Using Carry Forward in Longitudinal Data
Source:R/margot_impute_carry_forward.R
margot_impute_carry_forward.RdImputes missing values in longitudinal data by carrying forward previous observations up to a specified number of time points back. By default, it never imputes data for the final wave (end-of-study). Optionally, it can create indicator variables for imputed values.
Usage
margot_impute_carry_forward(
df_wide,
columns_to_impute,
max_carry_forward = 1,
time_point_prefixes = NULL,
time_point_regex = NULL,
require_one_observed = TRUE,
columns_no_future_required = NULL,
create_na_indicator = TRUE,
indicator_suffix = "_na",
indicator_as_suffix = TRUE,
verbose = TRUE,
impute_final_wave = FALSE
)Arguments
- df_wide
a wide-format dataframe containing longitudinal data.
- columns_to_impute
character vector of base column names to impute (without time prefixes).
- max_carry_forward
maximum number of time points to look back for carrying forward values.
- time_point_prefixes
optional vector of time point prefixes (e.g., c("t0", "t1", "t2")).
- time_point_regex
optional regex pattern to identify time points. Overrides time_point_prefixes if provided.
- require_one_observed
logical. if TRUE, only impute if at least one value is observed in the present or a following wave.
- columns_no_future_required
character vector of columns that do not require future observations for imputation. defaults to all columns if require_one_observed = FALSE, or none if require_one_observed = TRUE.
- create_na_indicator
logical. if TRUE, creates indicator variables for imputed values.
- indicator_suffix
suffix to add to the original column name for the indicator variable (default is "_na").
- indicator_as_suffix
logical. if TRUE, the indicator suffix is added as a suffix; if FALSE, it's added as a prefix.
- verbose
logical. if TRUE, prints progress information.
- impute_final_wave
logical. if FALSE (default), the final wave (end-of-study) is never imputed. if TRUE, the final wave can be imputed like other waves.