multi_transmat function

Creates a transition matrix for each item.

Needs an 'interleaved' dataframe (see interleave function). Pre-test item should be followed by corresponding post-item item etc. Don't knows must be coded as NA. Function handles items without don't know responses. The function is used internally. It calls transmat.

multi_transmat(pre_test = NULL, pst_test = NULL, subgroup = NULL,
  force9 = FALSE)

Arguments

• pre_test: Required. data.frame carrying responses to pre-test questions.
• pst_test: Required. data.frame carrying responses to post-test questions.
• subgroup: a Boolean vector identifying the subset. Default is NULL.
• force9: Optional. There are cases where DK data doesn't have DK. But we need the entire matrix. By default it is FALSE.

Returns

matrix with rows = total number of items + 1 (last row contains aggregate distribution across items) number of columns = 4 when no don't know, and 9 when there is a don't know option

Details

multi_transmat: transition matrix of all the items

Examples

pre_test <- data.frame(pre_item1=c(1,0,0,1,0), pre_item2=c(1,NA,0,1,0)) 
pst_test <- data.frame(pst_item1=pre_test[,1] + c(0,1,1,0,0), 
                                          pst_item2 = pre_test[,2] + c(0,1,0,0,1))
multi_transmat(pre_test, pst_test)