Non payment for incomplete surveys

If a participant fails to complete the survey am I within my rights to withhold payment. I do note there are some demographic questions participants can’t be obliged to answer but with the exception is it routine to deny payment for incomplete submissions.
And if that is acceptable, do I need to explicitly state that fact in the instructions?
Many thanks! This is my first online study and its a steep learning curve!

Hi Kelly

Yes, apart from Identifying personal information (and probably
other things such as the obscene, racist, psychologically harmful)
you can make answering a condition for payment.

This is usually done by using commands within your survey
software requiring an answer. In the free Google Forums for
example I can select “required” with a slider, such that the
participant is unable to go onto the next section, or post the
survey, unless they have made some answer to the question.

If the survey is not posted, then the participant will not get
to the completion link with the completion code, and after a
certain multiple of your estimate of the maximum time their
survey will be marked time out and there will be no need to
reject payment – they simply will not be paid – and the funds
will become available, and I think, a place will be reopened.

I can think of one exception, in that if a participant simply
returns to the launch page, and presses complete with no
code, then their submission will be marked " NoCode" and
they can be rejected on this basis. There are exceptions to
this too, in that if your example you set up your survey
incorrectly such that no participants get the completion
code then you will not be allowed to reject them all. But
participants attempting to complete using “nocode” is
rare. They might use this ruse if you started asking strange
and risky questions part way through the survey however.

I hope that helps,


Timothy Takemoto
Yamaguchi University

Hi Kelly,

The relevant Prolific rules on this are:

The participant skipped crucial questions, i.e. questions that are critical to answering your specific research question.
These questions must not have been shown as optional for the participants
Please note that demographic questions do not fall under ‘crucial questions’ because participants have the right to withhold such sensitive information (according to guidelines by the British Psychological Society*

As Tim suggests, these rules imply that there should be almost no situation where a researcher is manually rejecting participants based on incomplete responses. I.e., if the question the participant missed is set as required in the survey, then they shouldn’t be able to progress past it and receive a completion code anyway.

It’s also worth remembering that many IRBs/ethics committees regard it as mandatory for participants to have the right to decline to answer questions. So I’d tread quite carefully with this.

FWIW, I set almost all of my questions as optional and still get maybe one participant who misses one item out of every n = 500. Participants are wary of researchers rejecting them, even if it’s against the rules, so they tend to be conscientious about answering everything. If you get a lot of missing data it’d usually tend to suggest something has gone awry in the survey itself.

Hope that helps!