Direct workers who are waiting or without experiment spots to do other panel HITs

[markwhiting]

As a worker who has turned up to do an experiment, I may be disappointed if all the spots are taken. Alternatively, if I arrive early, I may want to kill some time working on another survey.

As a researcher, I want people who have come to an experiment to be somewhat satisfied, even if they can't participate, or have to wait to get started.

Directing workers to complete more panel hits, or at least, the next panel survey, seems like a good way to navigate this problem.

This issue can be closed when

• There is a mechanism for directing workers to do at least one next panel survey when no other activities are available.
• The redirection has been tested when there is an experiment active, and when there is no experiment. Aim for around 100 survey completions just so we really know it's working ok.
• The redirection is not receiving negative feedback or emails indicating confusion.

[markwhiting]

@JamesPHoughton feel free to edit the issue above as you see fit. I just wanted to jot down some thoughts around this.