Posted by: Gabriele Paolacci | February 18, 2015

Excluding MTurk workers who participated in your previous studies: An Excel solution

This document guides you through a simple method to avoid recruiting MTurk workers for your studies who already participated in a certain study of yours. The core of the procedure relies on Excel (as opposed to CLT or the MTurk API) to assign a Qualification to multiple workers at the same time. Using this procedure will allow you to exclude from the recruitment workers who participated in a previous related study (e.g., a study you are now replicating), and can be functional to other goals too (e.g., executing longitudinal research, building your own panel).

Update June 10, 2015: Arnoud Plantinga developed an script on R based on this method in which you don’t have to create the new variables yourself. You can download the script here.


  1. Thank you for posting this! It really helped me out!

  2. gives you greater control over your Mechanical Turk HITs. If you create your HITs through TurkPrime you can easily include/exclude people who took a previous study.

  3. This may be of interest to your readers:

  4. […] MTurk API or GUI allows you to create qualifications that filter out unwanted […]

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