Studying in different time zone skewing statistics

[David Resnick]

Hi folks,

I recently spent 3 weeks in a time zone 4 hours ahead of my usual time zone. I didn't have any problems with cards scheduled for the day. But I noticed that my study times were being logged according to my usual time zone, i.e. 4 hours earlier. This also led to 2 days showing as not having reviews.

I'm using the latest AnkiDroid 2.18.1 (anki 24.04.1) and have had FSRS enabled since it was available in a standard release. 

How can I avoid this in the future?

Thanks,

David

[snowtimeglass]

Hi,

I don't understand your situation enough, so I'm wondering about whether you can avoid it by adjusting the clock of your device to the time zone.

Regarding the recent case, you may want to try configuring the following setting:

'Settings' > 'Reviewing' > 'Start of next day' > set it to, for example, '0 hours past midnight'

Best,
Yuki

2024年5月28日火曜日 14:09:31 UTC+9 David Resnick:

[David Resnick]

I think you are right, changing the device time would do the trick. It might be nice to add this as a setting in Anki.

I was able to fix my review times so that I had it shown correctly that I didn't skip any days and was actually studying at 6 AM, not at 2 AM. You can see the result in stats here. 

This SQL script fixes review times (by updating the revlog table) to show my home timezone, which is 4 hours later than the timezone I reviewed in from May 6, 2024, at 3 AM (UTC): 1714954800000 to May 26, 2024, end of day (UTC): 1716700799000

BEGIN TRANSACTION;

UPDATE revlog
SET id = id + 14400000  -- Shift 4 hours later
WHERE id BETWEEN 1714954800000 AND 1716700799000;

COMMIT;

I used DB Browser for SQLite to execute the query and update the DB.

Posting here to help anyone else who wants to get better stats, and for me to reuse in the future :)

- David 

[David Resnick]

One last thing: I had to do a force sync with AnkiWeb for my update to be synced with AnkiDroid. Not surprisingly, Anki didn't realize it needed to the sync.

- David