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An Appurify Study: Fix Bugs & Climb the Apple App Store Ranks

September 6, 2013 · Krishna Ramamurthi

This is the first in a series of blog posts by Appurify on how to develop successful apps and make waves in the Apple App Store. Findings in this series are based on data gathered using Appurify’s pioneering mobile performance optimization platform which allows us to deeply analyze a wide variety of app performance metrics on real devices, alongside publically available data. Over the next several months Appurify will publish frequent posts covering the top concerns of app developers, including app store dynamics, the impact of iOS7 & Android 4.4 and the introduction of new iOS & Android devices.

The algorithms behind Apple’s app rankings are constantly evolving. What we do know is it bases rankings—central to an app’s monetization ability and long-term success—on a mix of several factors, including the number of downloads, download velocity, ratings activity, and the favorability of reviews.

In this post we will address the following question: How much does an app’s rating influence its discoverability, reviewing and rating activity, and ultimate rankings in the Apple App Store? We’ll also explore what app developers can do to maximize their app’s success, including performance optimization and testing.

For our analysis, we examined the top thousand ranked apps in the Apple App Store. The chart below shows the distribution of apps by app category with games accounting for about a third of the apps. Only 62 of these top apps were paid apps, while 590 of the free apps offered in-app purchases.


More than half of the top apps are ranked at least 4.5-stars. In fact, a sizeable majority of the apps (75%) were at least rated 4-stars. This finding is not surprising, but it is interesting to see how aggressive the ratings requirements are to be in the top 1000 apps:


Fix Bugs and Update = Get Better Ratings

So that brings us to the next question: How exactly do you get better star ratings? Of course, creating an app that people actually enjoy and like to use is important. But what else can you do?

In a previous blog post on how to avoid bad reviews (and ratings), we found that more than half of critical 1-star reviews in the Apple App store were due to performance issues. These complaints focused on application functionality and stability issues, slow network performance, and laggy client performance.

Releasing an app without addressing performance issues can have a huge impact on an app’s ultimate star ratings.

Fortunately, every update cycle in the Apple App Store is an opportunity to start fresh on the app ratings of your app. In fact, the ratings for “Current Version” are featured more prominently on search engine results and arguably matter more to the average consumer than ratings for “All Versions.”

Treating the update as an opportunity to address performance issues is important–­­releasing new product features that haven’t been stress tested sufficiently can hurt the ratings of an otherwise stellar application. For example, since its most recent update on August 16th, Instagram’s ratings fell by 1.5 stars mostly owing to concerns about bugs and performance issues:


A quick scan of the critical reviews reveal complaints mostly pertaining to the app crashing, freezing and taking too long to load. Many of these complaints revolve around Instagram’s newly introduced video feature. If it were not for these 1-star ratings, Instagram’s release would have achieved at least a 4-star status. Instead, it only got 3 stars.

In direct contrast to this is travel app’s latest update on June 16th:


In’s case, its reviews prior to the update had many complaints about crashes and poor performance. Since the update there have been almost no mentions of the app crashing, being buggy and so forth.

The importance of fixing bugs during the software update cycle cannot be overstated. Or better still, taking care of bugs, crashes, and performance issues prior to release can make a huge positive impact on reviews and ratings. The majority of negative reviews are performance related and can pull your app down.

Better Ratings = More Momentum

While it is clear app ratings can change for the better or the worse following an update, we wanted to see how this affected an app’s discoverability by consumers in the store. In particular, we wanted to see how much traction apps gained or lost owing to ratings alone.

To assess this, we looked at the number of reviews-per-day and ratings-per-day apps received following their most recent update.


What we found was that higher-rated apps attracted more reviews and ratings each day than poorly rated apps.

The effect is especially pronounced between 4-star rated apps and 4.5 rated apps with activity roughly tripling. The significantly higher activity enjoyed by the 4.5 star and 5 star apps is also self-evidently favorable for the most part.

The take away for app developers here is that every half star matters and could potentially improve the reviewing and ratings activity of your app threefold.

Ratings Can Affect Rankings

It’s a fact that higher-ranked apps enjoy a greater number of downloads, reviews and ratings. However, how does an app’s star rating figure into that?

To answer this question we separated the top thousand apps into three buckets (Top 300, 300 to 600, and 600+) and observed how the number of ratings an app receives per day (since the most recent update) varies by app ratings.


The chart above shows that ratings activity depends both on an app’s rank and it’s rating. Let’s give an example. Let’s say your company produces two apps. One is a 3.5 star app and the other has 4.5 stars, and last month they were both ranked in the 900s. However, last week you started running a new marketing campaign, causing both of their rankings to enter the Top 300. Not only was the 4.5-star app enjoying higher rating activity prior to the campaign, but now that effect is multiplied.

This tells us that the higher you move up in rankings, the more ratings matter. Having a higher-rated app could make all the difference in your app’s success and how far your marketing dollars go.

In fact, a recent article on TechCrunch explained how Apple might have started integrating app ratings directly into their app rankings algorithm. If true, this sends a clear message to app developers to focus on app quality and performance. We agree!


To summarize our findings, an app’s star rating bears a strong correlation to the reviewing and rating activity of the app in the Apple App Store, and can ultimately help improve rankings. Our specific findings:

  • 75% of the top 1000 apps have 4+ star rating
  • It is important to test apps for bugs/crashes and performance issues prior to release and before every software update
  • Remember to check for performance issues when pushing updates–a low-performing update can tank your rating
  • Higher-rated apps attract more favorable attention and are more likely to get more reviews and ratings following software updates
  • It’s not enough to just get to 4 stars. The uptick in ratings activity between 4 and 4.5 stars (and higher) is significant
  • App ratings and rankings are inter-related. The higher you move up the rankings ladder, the more app star ratings matter.

App discovery is a double-edged sword. Staying afloat and ahead requires a constant influx of “favorable-reviews” and “good-ratings.” The 15-minutes of fame in the top rank charts might not be enough to drive a sustained long-term monetization strategy for app developers. Testing and fixing app quality both pre-release and prior to update cycles can have a huge impact on the performance of the app in the Apple app store.

Appurify is passionate about this problem and is engaged in an analytics effort to gain insights on how app quality affects performance in the app store. If you’d like learn more about how we can help you improve your app’s quality contact us at