We want to make a longitudinal study about babies. A user should be able to write her email and the date of birth. Then the system should send email when the baby is, say, 30, 60 and 180 days old. The survey should be ongoing, so someone might be answering 180 days questions when other baby is just 30 days old. Questions will be different, they depend on assumed phase of baby skills.

I know this can be done using API and small external code, for example php to run from cron. But is there any easier way?

Hi,

If the questions are too different, I would do one survey per phase.
Upon the end of each survey, an invitation on the next srvey will be created, with a valid from date. Then a plugin would be sending the invitations when the validFrom is due.

We already have plugins for both of the tasks. Please contact me at gabriel@encuesta.biz

Thanks

I also have external code that will do this. In this case the user will use REDCap.

But I wonder how this has not been implemented in the core. Needs cron, but otherwise should not be very complicated. And the need seems clear, for example after selling something send later a question about how the product etc.

I know this can be done using API and small external code, for example php to run from cron. But is there any easier way?

In my opinion this is the easiest way.
A few lines of code in php that queries the database, triggered by a cron job each morning, and send out the actual invitations.

Joffm