Excluding Mturk workers from surveys in Qualtrics (and elsewhere)
A little while ago I wrote about how to replace the use of confirmation codes with the use of Mturk’s worker ID. It really serves a variety of function other than getting rid of pesky confirmation codes. For instance, many people want to exclude workers from a survey if they have done certain past surveys. Other than data-basing every worker and survey you run (something I recommend, but that’s for another time), you can use this method which matches the respondents worker ID against a black list of past respondents.
First, you need to get and store the worker ID in Qualtrics. I covered this here. Skip the senseless writing at the beginning and just read the comments inside the code and everything below it.
After completing that, all you need to do is make a comma separated list of your worker IDs to exclude, and program a logical branch in Qualtrics. To make the list, you should either have a data file or Mturk batch file with the IDs in a column. Put the column in a new spreadsheeet, and put a comma in each cell to the right of an ID (just type a comma next to the first ID then CTRL click and drag in Excel). Highlight and copy both columns. In your Qualtrics survey flow, add a new field underneath your workerId embedded data field. Name it whatever you want, but I use exclude. For the value, paste the string of IDs.
Last, create a branch element with the logic “IF EMBEDDED DATA exclude CONTAINS workerId” and make that go to a block containing a text question politely asking them to return the HIT, then add an End of Survey element. You may get some complaining emails for making someone accept a HIT just to ask them to return it, but it really does not affect them negatively (I even asked Amazon about this). Everything should look like this:
If you are using something other than Qualtrics, I have used similar methods in SurveyGizmo, Survey Monkey, and in custom programs, though with different implementations. If you need help using this in a different venue, leave a comment.