Setting a time interval for an automatic message

Question

I have a form where a user needs to set how often and at what time a certain report is send from the system. The report is created and sent automatically. In the current system the form looks like this; The time interval means that the report is sent every 60 seconds. Time offset means the offset from an equal minute. With the values in the image, the report would be send at 10:00:15, 10:01,15, 10:02:15, etc. If the offset would be 0, the report would be send at 10:00:00, 10:01:00, and so on.

This design is quite difficult to understand. What would be a better to tell the user what the time interval and offset mean? Should I add examples? The use case here is that usually send interval is at an equal minute mark, but sometimes the offset is needed. Furthermore, there might be rare cases where one would want to send the report, for example at every 45 seconds.

Answer 1

If possible, try to use time intervals that are easy to calculate, and allow them to explicitly choose a delay or 'offset'.

I might not understand your use case, but it seems there is two concepts: report generation and report delivery.

I'm not sure who your users are, but words like interval and offset seem more to conform to a database model, rather than how people would speak of this using plain language.

There's an article from Nielsen Norman on this.

In our recent usability study with domain experts in science, technology, and medical fields, we discovered that even highly educated online readers crave succinct information that is easy to scan, just like everyone else.

Your example: interval units and mental math

Is there a reason for intervals that are less granular than one minute? With a 90 second report offset every 15 seconds, it can get a bit confusing.

One option if the default is 'no offset' (meaning 'send it immediately'), you could give them a choice to explicitly choose an offset, and update some example text below after they input the value. My example text could be a bit clearer, but here's a quick sketch:

Answer 2

To expand on Mike M's solid suggestion, you might want to research if you can limit the number of "time intervals" to a handful of meaningful options. See the below screenshot form Apple Mail for an example.

If that'd work for the offset, too, you could also further consolidate the "Send this report" setting from a radio button pair plus text field into a single popup menu.