Convert a "Yes-No", "True-False" or "Checkboxes (Multiple Answers)" question in REDCap to a factor holding "Yes" or "No or Unknown". Technically "yes" or "checked" (ignoring case), 1 or TRUE responses are converted to "Yes" and all other values to "No or Unknown". Also see make_yes_no_unknown().
make_yes_no(x)
Arguments
x: x variable to be converted to hold "Yes" or "No or Unknown"