There are a number of times when as part of a study you want to allocate participants to different conditions. The traditional way to do this is to creating multiple independent surveys and then use a common initial page to create a random number and then send the participants on to one of the surveys behind the scenes. With qualtrics there are a few ways to achieve this kind of distribution to different conditions.
Using Survey Flow
If the surveys are mostly the same with only small variations then it is often better to create all the variations within one survey
If the surveys are mostly the same with only small variations then it is often better to create all the variations within one survey and use survey flow to create the conditions and present only the relevant information for each condition. In my view this is the preferred option with several advantages:
- You keep everything in one place and don’t have to keep jumping back and forward between surveys.
- You can control multiple aspects of the conditions – it is a more fine-tuned process than just having a different survey for each condition.
- If many questions are in common then it makes sense to only have them in one place. Otherwise if you decide to change the wording of questions you need to make those changes in multiple surveys or risk the outcomes not being comparable.
- The data all ends up in one file instead of multiple files. This avoids the need to merge survey files and deal with matching variable names. (Make sure though that you create an embedded variable with the condition number so you can tell which version they did!)
For some more information about combining multiple conditions in one survey, see also this post that I created earlier.
Using multiple surveys and a master survey for redirections
There are times when it can be more convenient to have multiple surveys but one link to distribute to potential respondents. These might include:
- If you already have multiple versions of a survey from previous research and you simply want to use the same traditional approach without combining them all into one survey structure.
- If you have multiple very different surveys and you just want them all to be allocated in a balanced way. (For example if you had several research students running different but related studies. You want to allow all to equally benefit from some organisations willing to distribute your questionnaires, but the organisation just wants to send out one survey link to its mailing list.)
…the master questionnaire can be completely empty apart from the survey flow mechanisms.
In these kinds of cases it may be easier to keep the different questionnaires separate and use a master survey to allocate respondents to the different questionnaires. This technique still makes use of the survey flow technique but in this case the master questionnaire can be completely empty apart from the survey flow mechanisms. The flow options then do the random allocation to different surveys. The user will be given the master survey link but when they click on it they will be redirected to one of the actual surveys.
The psychology tech support staff at the University of Kent have come up with a nice set of simple instructions for doing this, so you can follow their instructions here. It is a PDF and will open in a new page.
In most cases I recommend using a single questionnaire in qualtrics and using survey flow (or conditional questions) to change what the user sees to represent different conditions. However, if there is good reason for using multiple surveys, the same survey flow idea can be used to create a master questionnaire.