Pseudorandomization with files
In the experiment, stimuli are 14 pairs of questions (28 questions in total). Questions in the same pair should not appear successively. In the loop, variables are from a csv file. I followed the example in pseudorandomization and tried to constrain
pair for the purpose.
However, the red arrow indicated that
Invalid column name: pair while the file did contain the pair variable.
I wondered if
constrain only works when the variables are directly from table in loop item?
Thanks in advance!