Negative duration detected while calculating form-filling-time

I was analyzing time-taken to fill forms by enumerators. To do that, i was subtracting start-time from end-time (both meta-data).
Surprisingly, I stumbled upon a submission which returned negative duration. How is that even possible? Any clues.

Hi @mohan_n,

Would you mind giving another workaround to capture the data entry time that has been outlined in a discussion previously:

Have a great day!

I guess the problem lies somewhere else. Attaching the table view of the data. the end-time is less than the start-time.

what could be the issue?

Hi @mohan_n,

Thank you for the details. Will get back to you soon.

Have a great day!

From the look of it, it seems this is only in one of the responses? Could you confirm as such?


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There are many such submissions of the project which have very low form-filling-time. The form has around 100 questions and generally take 10-15 minutes to fill. One of the question is a repeat-group with text-type questions in it.
I have found values like -2, 0, 2, 3 minutes. etc. And today i have received more submissions one of which is -5 mintues.
I was about to make decisions based on average duration I calculated. But then when i saw a histogram of the data, i found this bug. And now I doubt whether the start and end times that i am receiving in submissions are indeed reliable.

Note: All the forms are being submitted through Android mobile device.

On start and end time, these are picked based on the device time. The only logic for an older start time compared to end-time is if the device time was adjusted backwards while the questionnaire was still open. I suggest you do the following,

  • Confirm whether the negative times are coming from the same device or they are coming from different devices i.e. are they concentrated around the same data collector/s?

  • Confirm whether the device causing the issue are specific is web-form or collect application.

This would help us figure out the issue.

On a workaround, I prefer asking that you create a calculate question that calculate time at particular points on the questionnaire. You can make the calculation be such that time is only recorded once and does not change.