App Store Optimization (ASO) (4/5): Ratings & Installs or: The Google Play Store Search Algorithm

Another part on App Store Optimization. Finally. By the way, if you are from Germany: There is an article on App Store Optimization in the current Android 360. Go and get it (if you want)!

If you are new to this series, I recommend starting from the first article on App Store Optimization. If you don’t want to read that much, this article can still give you valuable information on its own.

Parts of this series on App Store Optimization are:
1. Keywords
2. Description

3. Icons
4. Graphics
5. Videos

6. Ratings
7. Installs
8. Users

While the last articles covered Icons, Videos and Graphics, we will go more into the search algorithm of the Play Store (I still need to get used to this name), an area that probably fits most developers better. Because this article will cover big parts of how the the Play Store search algorithm (most likely) works, there will be a summarizing Play Store algorithm-part at the end.

6. Ratings

When it comes to two equal apps, the app with a better rating will receive a better ranking. When your app does not have any ratings yet, it will internally get a composite score representing the quality of the apps you published before. This means: Ratings are important. But how to get lots of positive ratings? Well, there are several methods, one of them is to buy them via certain dubious websites (I ‘ve never tried that), another way is to simply ask your users for ratings. This step is actually pretty simple but it can and most likely will improve your ratings a lot, provided that you are making it right:

  1. Ask your users using an AlertDialog. While a beautiful little button in your main menu may be nice, users have the tendency to ignore things that want something from them (like they do with banner ads) and keep them from doing what they actually want to do (explore your app). This is why a one- or n-time alert dialog will catch much more attention than a button that is just always there. Personally I prefer the one-time to the n-time version.
  2. Don’t ask them the first time they use your app. That’s pretty obvious. How should a user know how to rate your app when he didn’t even use it? Instead, wait until he used it five or six times or played through the third level or so. When a user uses an app a couple of times, this is a good indicator that he actually will give you a better ranking.
  3. Give them a chance to opt out. You shouldn’t force your users to rate your product but give them a chance to say ‘later’ or ‘don’t ask me again’. When a user decides not to rate a product but gets annoyed by repeated dialogs, there will come a time when he ranks it with very little stars.

 7. Installs

Installs are important. They are important for you, because many users equals many dollars. But they also are important for the Android Market Search Algorithm. To be more precise: The ratio of active installs to total installs, respectively the refund rate. This will have special weight when your app is published the first time and there are not enough comments to give your app a ranking and no other apps to give your app a composite score.

Since gaining installs and keeping active installs is very important, it’s important to have a well designed and tested app. Boosting user numbers by force can be a very expensive task, that’s why it’s even more important not to lose existing users. To increase the number of downloads of an app, the well known classic methods like writing blogs, creating viral content, paying for ad space or ASO can be applied.

The the Google Play Store Search Algorithm

The search algorithm of Google’s website is known to be a black box of which nobody except Google knows how it works exactly. Guess what: With the Play Store search algorithm, it’s exactly the same. Still, by try and error and a lot of observation, patterns can be recognized. Here’s what the Play Store search algorithm roughly looks like:

temporary relevance * t + keyword frequency  in the title * u + keyword frequency in the description * v + ratings * w + composite score * x + active installs in per cent * y + black magic * z

Temporary relevance here means the acceptance of the users over a small time period, or in other words the download rates in the last days and weeks. As you can see there is a little ‘black magic’ involved, this is a synonym for uncertain influences like the +1-button, the percentage of solved known bugs with every new update, the relevance of keywords used in the recent changes-description and all the other small and uncertain things.

After various observations, the following rough order can be assumed:

w >= t >= y > u > v > x

z, representing the weight of various factors, is ignored.

Now, when optimizing your app for the Play Store, you can try to improve your app’s environment based on this order, meaning for example: “Let’s put our main effort into a solid UX, a non-annoying dialog with a high conversion rate asking users to rate us high and a good description.”



You maybe noticed that the Play Store search algorithm changed a lot in the last 18 months. ASO is very dynamic. New changes need to be observed and classified as soon as possible, so it always stays exciting.


I’m open to your suggestion, criticism and questions. Please leave them in the comments.


  1. Nice details.. a tip on keeping user installs longer: provide unlockables!

    Give your app or game something that can be unlocked when the user has done certain things, like scored above 1000 points, or reached stage 7 of the game, or started the app and logged in for 10 times.

    Even giving rewards that users can brag about, like what the Heyzap app does can help improve the active installs. Example: Rewards like “Night Owl” if the user logs in at night a few times in a row. Some people just love the badges/rewards!


  2. I’ve been waiting for your post on the Google Play App Store algorithm with bated breath. Very interesting! I’m not sure if you were talking about doing a keyword search in the App Store, or the listing in particular categories, like games. I would speculate that when you do a keyword search, that the most important factor in ranking search results is what you call “u” (keyword match in the title). Maybe that’s just obvious, if you are searching for keywords. Second after that, in my estimation, is what you call t (temporary relevance), then perhaps user ratings (w). And so on.

    Great food for thought, keep it coming!

    • Hi Lucy,

      thank you for your comment.
      Sorry for being not clear enough, it’s about keyword search. For a listing in categories, u and v had to be 0 and the priority had to be different. I think the relevance of w and y has to be taken serious because they and the composite score are the only parts of the Play Store’s algorithm officialy named by Google (and because my observations show equal results of course).

      Thank you again, best regards

  3. great post :D
    This is really a very informative post. I’m looking for your blog.

  4. Chris Knight

    2012/03/11 at 08:37

    Great post and great series. I’ve been working to implement a number of things to improve my search ranking and its starting (ever so slowly) to work. In particular I relate to your section above on ratings. Since implementing in my last release a popup asking for users to rate my app (after a certain number of days and uses), my ratings have doubled (not very difficult!) and its had a positive effect on my ratings.

    Anyway a few questions on the search algorithm above. You say “the percentage of solved known bugs with every new update, [and] the relevance of keywords used in the recent changes-description” could play a role in an apps ranking in search results. Does this suggest that saying in recently changed section that bugs have been fixed is potentially a positive influence on your ranking?

    Finally, by “keyword frequency in the description” do you mean “the number of keywords which appear in your description (regardless of count)” or “the number of times keywords appear in your description”? My experience suggests the former.

    Anyway, thanks again!

    • Hi Chris,

      I mean the amount of bugs you marked as “old” in the developer console. And both for the keywords, but the effect of repeated keywords is really small.

      I’m glad you like it,
      best regards

  5. I totally miss the mentioning of backlinks to your app – I am pretty sure, that they have the one or other influence – but I am not sure how google work with it now, because they use a strange construct of redirecting from the old links…

    Also be aware that every result you see is localized for the different countries – so one from US will get different results than one from germany.

    Robo Miner was in the trending list someday (I was told) but I was not able to see it, because I am located in spain.

    Nice Artcile!

  6. Inspired by your observations I added a “rate this app” button to my slot machine game in the last version. The invitation to rate the app appears whenever the player earns an achievement medal and this seems to work well in terms of encouraging good ratings and comments.

    I released the new version just under a week ago and so far 60,000 users have upgraded out of a total active install base of 175,000 users. The number of ratings of my game has doubled from about 400 to just over 800 and the average rating has risen from 3.9 to 4.2. That’s a fairly significant rise in my mind.

    Unfortunately all these extra positive ratings don’t seem to be helping my app store ranking. Just before the new version was released my game was at 62 in the free cards and casino games category, now it has slipped down to 68. The only reason I can think of for this is that the new version seems to have prompted quite a lot of users to uninstall the app. The total active installs has dropped from 182,000 to 175,000 since releasing the new version which is a steeper decline than previously.

    This suggests to me that the percentage of active installs has a higher weighting than the number and quality of the app’s ratings when it comes to app store ranking.

  7. Johannes, this is a great series on app store optimization, thanks for putting it together and sharing. The idea to prompt app users to rate your app is a good one – as several of your commenters have noted, just instituting some notion of a prompt will really drive the volume up.

    You can go a few steps better than just prompting them to rate the app. If you’re really trying to figure out how people feel about your app and to delight them (only delighted people will really say great things about your app), you can do a better job of qualifying if they’re ready to rate you and hearing from the people who think you have work to do.

    We shared our thoughts about this in our blog post, Better ratings for your applications and a lot of developers are using our in-app feedback and communications tools for just this purpose.

    When developers can control when the prompt is shown to your app users and then optimize it, based upon results, not only does the volume increase, but the actual ratings really skyrocket, leading to large increases in app store placement. We highly recommend tailoring your prompts to your audience!

  8. Nice Post!!..Learned a lot but I would say that Android App Marketing includes Pre Launch Marketing as well.. As now day in the vast ocean of Android apps , marketing norms and strategies are getting changed day by day. I have shared a lot about this in my CreatioSoft Android Marketing Forum. But apart from this I would say that nice collection of Android app Marketing strategy.

  9. Johannes,
    you left me impressed. One of the most comprehensive guides I’ve read about ASO. Thank you very much for the effort, I look forward to the last point.

  10. Hi Johannes, this is a very great collection of information you got right here and I am especially interested on your take how the Google Play Store works. Since this post is a little older what do you think has changed about it?

    Thanks mate, and I would appreciate if you would take a look at my blog as well. :)

    • HI Maximilian,

      thank you for your comment.
      Of course a lot has changed over time. Right now the keywords used in the user reviews have become of high importance.

      I’ll take a look at it, thanks.

      Best regards,

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