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Monthly Archives: February 2010

For the last couple of days, iPhone developers with apps on a top 100 list have become concerned that recent changes in the App Store ranking algorithm may be affecting their livelihood.  No one has provided conclusive proof one way or the other whether these ranking algorithm changes are a glitch in the system, or the latest attempt by Apple to make the App Store work for developers and consumers.  The end result is that many apps that haven’t seen a top-100 list position for months or ever, can now be found on a top 100 list.  Here’s what we know about the situation as it currently stands.

App Sales Information has been Delayed

Developers are reporting that their daily sales reports from Apple, which have been promptly delivered without interrupt daily for over a year (excluding the Christmas holiday break), are now running over 24 hours delayed.  This has never occurred before and is pointed to by some to indicate that there is a ‘glitch’ in the system.  The delayed sales data could then be the cause of the changes seen in the ranking algorithm.  The ranking algorithm depends on real-time sales data to calculate popularity.  If the real-time sales data is unavailable, or delayed for some reason, then this could explain why the popularity algorithm is confused.

All-Time Sales, whether Paid of Free, are weighted Higher than they used to be

Many of the apps that have jumped up in the rankings share a common feature – they have had a large number of sales in the past.  This could be due to being featured by Apple or due to the app being free. Two of IMAK Creations’ apps jumped into the top-100 of their category.

Hold On!, which was our 2nd app we created and on the store day 1, started out free and accumulated over 80,000 downloads while free. We then updated it to support multiplayer over Bluetooth and made it $0.99.  It has since had around 500 downloads while paid.  Yesterday, it jumped to #97 on the top-100 Productivity apps in the US App Store. Today it has fallen off of the top-100 list, but is still ranked much higher than it should be according to the old ranking algorithm.

Brain Blaze Divide is another one of our apps that we had free for a long time.  During this time, it accumulated over 65,000 downloads. While paid, it has had around 500 downloads as well. Yesterday, it jumped right next to one of our other Brain Blaze apps, BB Vocab, at #87 in educational games.  BB Divide is today still #90 and BB Vocab, which has been in the top 100 educational games list for months, is now off the list.

Free to Paid is Back ??

Early in the App Store days there was a loop-hole that could be exploited to get your app onto a top-100 paid list.  It was fairly simple. You just had to make your app free for a while.  At the time, free and paid downloads were treated equally. And since users prefer free apps over paid apps at a ratio of about 100 to 1 (based on our sales data), making your app free for even a day could dramatically increase your paid ranking once you made your app paid again.

In order to gain some insight into the current ranking algorithm, we changed the price of two of our free apps to paid.  That Ain’t It! Trivia – Lite Edition is the lite edition of our popular That Ain’t It! Trivia – Game Show.  It has been on the store for a number of months and has had a little over 20,000 downloads. It has been in the top 25 to top 50 of free trivia games in the US App Store during this time. After raising the price to $0.99 yesterday, it did not make it into the top-200 of paid trivia games (according to http://topappcharts.com/search.php?string=that+ain%27t+it&show=search&price=any).

However, our That Ain’t It!™ MJ Trivia special edition Michael Jackson trivia game, which has over 45,000 downloads since it was released in Oct. 2009, jumped onto the PAID music game list at #83 (in the US App Store).  This is conclusive proof that free app sales are currently being included, directly or indirectly (e.g. via rating or review count), in the calculation of paid app top-100 ranking positions.

One more data point which could be considered a control case is ColorTilt, our most popular application which has never been free.  It was once #3 in the US App Store and had 30,000 downloads during the first month of the App Store.  It then disappeared off of all top 100 lists and after a major update has risen again into the top 10 of educational games.  It has over 65,000 downloads total and has not appeared to have been affected at all by the latest ranking algorithm change.

CONCLUSIONS

By my analysis, the top 100 rankings have always been determined by a popularity metric that is based off of both an apps average daily sales over the lifetime of the app and an app’s average daily sales over the last 3 days (and probably some other time periods in between, like 2 weeks).  If there was a glitch in the sales tracking software that is causing a delay in reporting sales number to developers, then this glitch may have made it necessary to remove the 3-day sales average from the popularity equation and give a larger weight to all-time sales.  So, it may be that free app sales have been counted all along (obviously not 1-to-1 anymore, but perhaps 10 free equals 1 paid), but the weighting was too low to matter.  Once sales reports are produced in a timely fashion again, I predict that the ranking algorithm will return back to what it was a few days ago.  This may not help developers whose apps were knocked off of the top-100 list, because it’s much more difficult to climb onto a top 100 list than it is to fall off.