rasch_testlet function

Create testlets of survey items for a Rasch Model

rasch_testlet(df, vars_metric, testlet_strategy, max_values, resp_opts)

Arguments

• df: a data frame of individual survey data, where each row is an individual
• vars_metric: a character vector of items to use in the Rasch Analysis
• testlet_strategy: a list giving the strategy to take for creating testlets, passed to rasch_testlet(). One element of the list per testlet to create. Each element of the list must be a character vector of column names to use for the testlet. Optionally, name the element of the list to give the name of the new testlet. Otherwise, the new testlet will be the original column names separated by "_". Default is NULL, to not create testlets.
• max_values: a tibble with two columns, var equivalent to vars_metric and max_val with their corresponding maximum possible values
• resp_opts: a numeric vector of possible response options for vars_metric. Must begin with 1. Default is 1:5

Returns

a named list with: - df: new df after creating desired testlets

• vars_metric: new vars_metric after creating desired testlets

• testlet_strategy: new testlet_strategy after creating desired testlets

• max_values: new max_values after creating desired testlets

Details

If high local item dependence is observed (i.e., residual correlation) is observed between items, it may be desirable to combine them into a testlet. This code creates the testlets as desired.

See Also

Other rasch functions: rasch_DIF(), rasch_df_nest(), rasch_drop(), rasch_factor(), rasch_mds_children(), rasch_mds(), rasch_model_children(), rasch_model(), rasch_quality_children_print(), rasch_quality_children(), rasch_rawscore(), rasch_recode(), rasch_rescale_children(), rasch_rescale(), rasch_split_age(), rasch_split()

Other children analysis functions: rasch_df_nest(), rasch_drop(), rasch_mds_children(), rasch_model_children(), rasch_quality_children_print(), rasch_quality_children(), rasch_recode(), rasch_rescale_children(), rasch_split_age(), rasch_split()