Recode a long format data frame to a long format IRTrees data frame in the case when items have the same tree structure
LtoL_single.tree(
data,
cmx,
id.col,
item.col,
resp.col,
covar.col = NULL,
time.col = NULL
)
a long-format (person-item-response) data set
a a category-by-node mapping matrix
the person ID column
the item ID column
the response column
columns containing covariates
the time column. If not NULL, time.col
should be nested in id.col
, since it indicates repeated measures within persons
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.