rasch_testlet {whomds}

Create testlets of survey items for a Rasch Model

Description

Create testlets of survey items for a Rasch Model

Usage

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

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.

Value

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

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()