We’re changing the way we calculate add-on usage statistics on AMO so they better reflect their real-world usage. This change will go live on the site later this week.

The user count is a very important part of AMO. We show it prominently on listing and search pages. It’s a key factor of determining add-on popularity and search ranking.

However, there are a couple of problems with it:

We count both enabled and disabled installs. This means some add-ons with high disable rates have a higher ranking than they should.

It’s an average over a period of several weeks. Add-ons that are rapidly growing in users have user numbers that are lagging behind.

We’ll be calculating the new average based on enabled installs for the past two weeks of activity. We believe this will reflect add-on usage more accurately.

What it means for add-on developers

We expect most add-ons to experience a small drop in their user numbers, due to the removal of disabled installs. Most add-on rankings on AMO won’t change significantly. This change also doesn’t affect the detailed statistics dashboard developers have access to. Only the number displayed on user-facing sections of the site will change.

If you notice any problems with the statistics or anything else on AMO, please let us know by creating an issue.