Recode a wide format data frame to a long format IRTrees data frame in the case when all items have the same tree structure
WtoL_single.tree(
data,
cmx,
id.col,
resp.col,
covar.col = NULL,
time.col = NULL
)
a wide-format (person-by-item) data set
a a category-by-node mapping matrix
the ID column
the columns containing the item responses
columns containing covariates
the time column when there are repeated (longitudinal) data
Many examples of mapping matrices are given in the vignette. Columns may be specified by numeric index or by name. Response categories must be coded with consecutive integers starting from 1, not 0. Missing data should be properly represented as NA.