How to run an online experiment across multiple websites

A guide to creating links from one site to the next that preserve a unique ID for the participant

Preface

This document explains how to link between PsychoPy experiments on pavlovia, and other systems like SONA, and Qualtrics, while preserving the same participant number, such that responses on all the systems can be identified later as having come from the same participant, without resorting to using personal information that would reveal the participant’s identity (the recruitment systems like SONA are the only systems in the loop that knows how to map the anonymous information to the identity of the person).

Figure 1: Websites joined by open arrows send each other data like participant id; experiment id; and completion tokens, in query strings that are part of the URL. Black filled arrows pointing down into the data area indicate that the website has acquired some self-contained data and writes it its own filesystem. At the end of each participant’s run we need to be able to gather those separate datasets into a master dataset that contains all that participant’s scores, separately from the other participants’ scores.