Lesson 3 - Prioritizing Relevance, Difficulty and Traffic

Now let’s get to the core of app store keyword optimization. There are three characteristics of keywords that you have to understand. You will examine every keyword idea based on these criteria. What we are about to show you applies to both the Apple App Store and Google Play.

  • Relevance
  • Difficulty
  • Traffic

The biggest mistake that publishers make is selecting keywords solely based on traffic volume. While it is ideal to rank for keywords that get a ton of searches, relevance and difficulty are actually more important when it comes to getting downloads.

There is one exception. You want to make sure that the keywords you choose are getting at least some traffic. It doesn’t make sense to rank #1 for a keyword that nobody is searching for.


Relevance is the most important criteria when it comes to choosing keywords.To be more specific, your keywords need to be terms that people would search for to find your app.

Put yourself in the shoes of your ideal user. Think about technical terms, abbreviations and phrases they might use.

Since you are so deeply involved with your app, it can sometimes be hard to get an objective perspective as to what people would search for. Friends, family and even random strangers can be great sources of relevant keyword ideas.

The next lesson will give you a lot more tips on how to uncover excellent keyword ideas. But for now, just keep in mind that relevance should be your primary selection criteria.


Next, you want to find out how hard it is to rank for each keyword on your list. Different ASO platforms measure this in different ways.

We quantify it with our Difficulty Score. It estimates how hard it will be to rank in the top 10 for a keyword. We use a scale from 0 to 10, with 10 being the most difficult.

When doing research for iOS apps, you will see Difficulty Scores for both iPhone and iPad. Since there are different scores for each device, you need to take this into account when choosing your keywords.

If you have an app that is only for iPad, then you will only focus on that Difficulty Score. If you have a universal app, then you have to take both scores into account.

There is only one Difficulty Score for Google Play Android apps.

Difficulty is much more important than traffic. It doesn’t matter if there are a million searches a day for a keyword, if you rank #512 for that keyword.

Nobody is going to scroll that far to see your app. It is much more beneficial to rank #1 for a keyword that has less traffic.

It is important to note that keywords with higher Difficulty Scores generally have more traffic. This is not always the case. But since frequently searched keywords are most desirable, they will be targeted much more often.

The next question we usually get is: “What is a good Difficulty Score?” That depends on your app.

If you have an app that is more established and already has a lot of downloads, you will be able to rank well for keywords with a higher Difficulty Score. If you are just starting out, then you will have to target lower Difficulty Scores. Let’s examine this in a little more detail.

Established Apps

If your app has been available on iTunes or Google Play for more than a month and you have already done some optimization, figuring out your target Difficulty Score is simple. Just take the average of the Difficulty Scores that you currently rank in the top 10 for and use that as your target Score.

For example, let’s say that this is a sample of your top keywords and how your app ranks for those keywords. You have a universal iOS app, so you need to take into account the keywords for both iPhone and iPad.

In this case, you would average the Difficulty Scores of the first two keywords because your app ranks in the top 10 for them. The keyword “enigma” would not factor in to this calculation. Although the rankings for this keyword are still quite good, they are not in the top 10 and should be ignored.

This would give you at target Difficulty Score of:

2.6 + 3.7 + 4.9 + 5.1 = 16.3

16.3 / 4 = 4.0

So you should target keywords that have a difficulty score of 4.0 or less.

Our Difficulty Score is an excellent approximation of how hard it is to rank for a keyword. But keep in mind that it is an approximation. Conditions on the app stores change all the time, so you need to continually test and track your keywords to improve your rankings.

For example, let’s say that you want to add 10 new keywords to your app. They all have a very similar Difficulty Scores. After you add your keywords to your list, your app might rank in the top 10 for eight of those keywords.

Since the ranking algorithms for iTunes and Google Play are closely guarded secrets, nobody really knows why you didn’t rank in the top 10 for those last two keywords. The best thing to do is to just replace them with keywords that have a similar Difficulty Score and track the results.

Once you get a feel for how Difficulty Score affects your rankings, you will understand why it is so important.

At this point, you may be wondering what the Difficulty Scores of your current keywords are. You can find out by using our  free trial. You might be surprised at what you discover.

New Apps

If you have a brand new or unpublished app, or an app that doesn’t have any top 10 keywords, you cannot determine a target Difficulty Score. In these cases, we recommend targeting keywords with a Difficulty Score of 3.0 or less.

Once you publish your app or submit an update, you will have more data to work with and can then start making the necessary adjustments. It can be hard to find one-word keywords with a score of 3.0 or less, so remember to also look for multiple-word keywords.

Note: Keywords can contain one or multiple individual words. The word “castle” is a keyword, but the phrase “castle defense” is also referred to as a keyword in ASO.

For example, here are the Difficulty Scores for the keyword “fight.” The results for both the Apple App Store and Google Play are listed. With Difficulty Scores of 7.4 and 8.6, this is a very hard keyword to rank for.

But if you get more specific and add another word like “sparring,” the ranking difficulty drops significantly. This is especially true for iOS apps.

So start thinking about keyword phrases that can help you lower your Difficulty Score. Getting more specific increases the chances of ranking well for your target keywords.


Now we come to traffic. Again, different platforms will measure traffic in different ways.

We created a Traffic Score, which is our estimate of how many searches a keyword gets. It is on a scale from 0 to 10, with 10 being the most searched for keywords.

Assuming that the Traffic Score is above zero, it should only factor it into your keyword selection process if you are trying to decide between keywords that have similar relevance and Difficulty Scores.

For example, let’s say that you want to replace one of your underperforming keywords in your iTunes keyword list. You are trying to decide between the following two keywords.

Keyword #1:

  • Traffic Score: 5.3
  • Difficulty Score: 4.4

Keyword #2:

  • Traffic Score: 6.2
  • Difficulty Score: 4.4

In this case, since you can only choose one keyword, you would choose keyword #2 because it gets more traffic.


When you sit down to research your keywords, remember R.D.T., or Relevance, Difficulty, Traffic. That is the order of importance of the three selection criteria.

In our next lesson, we will show you exactly how to track your keyword rankings,research your competition and brainstorm for amazing keyword ideas.

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