A subset of iPad app developers in the US have been significantly hit by a ranking algorithm change in Apple’s App Store, causing some applications to fall heavily in the charts.

Apple occasionally changes the way its App Store ranking algorithm works to ensure a level playing field, which can impact rankings, download volumes, and other metrics.

App developers first took to social media a few weeks ago (17 July) to outline some strange activity on the store, after Apple seemingly implemented a new algorithm change earlier this month.

The iPad Facebook App, for example, was ranked as the seventh highest on the store on 16 July, but fell to 858th the following Monday (20 July). By midweek, it was back up to ninth in the rankings.

However, while Facebook recovered, TechCrunch reported that not all developers saw their applications fluctuate in the same way.

Apple never announces such changes, nor does it reveal the modifications it implements, but movement of popular and high ranking apps like Facebook, for example, is one of the best indicators that Apple is making an alteration.

Another good indicator for an algorithm change is the keywords associated with top apps. Indeed, a number of titles, including Facebook, Twitter and Instagram, have reportedly seen a large change in the keywords they rank for since 17 July.

“Unusual” App Store activity
TechCrunch said it spoke to more than a dozen application developers since the issue began, and the majority saw a massive drop in the charts.

Craig Palli, chief strategy officer at mobile marketing firm Fiksu, told TechCrunch last Wednesday the company observed unusual App Store activity which affected iPad rankings for several days.

“The apps that dropped have jumped significantly back up, but not all of them have returned to the ranks they were at before the drop.”

Developers will no doubt be concerned that a massive drop in rankings was caused by a longer term Apple adjustment, and analysts have questioned why Apple would try to manipulate app rankings deliberately.

According to Dan Held, co-founder of Analytica, the purpose of the change could be based on accurately ranking apps based on a criteria “Apple deems quality”.

“They may have found a large exploit some app developers were taking advantage of, but this seems more like a very large change of what Apple sees as important ranking factors – reviews, downloads, keywords, etc,” Held said.