# Building a Systematic Process for ASO With the CRO Loop

- Link: https://phiture.com/asostack/building-a-systematic-process-for-aso-with-the-cro-loop-d1c4bc7ca725/
- Published: 2018-12-12T21:48:39+01:00
- Author: Aude Boscher

#### The Conversion Rate Optimization Loop: A framework for increasing conversion rates via app store optimization.

_This article was co-written with _[_Stuart Miller_](https://www.linkedin.com/in/stuart-miller-a27b7115a/)_,
Design Lead at the mobile growth and ASO consultancy Phiture._

![](https://miro.medium.com/max/3200/1*i7Od_zu8Jip5aXqTOTquYA.jpeg)

_“My keyword rankings are shooting up, my search impressions have never been so 
high, but my listing doesn’t seem to be able to convert enough of those views into
installs”. Should you face this problem today, then you’re reading the right article.
There is no doubt that today, conversion rate optimization (CRO) is a core component
of your ASO efforts._

Without assets optimized for conversion, your visibility efforts and impression 
gains will be wiped out. Indeed, 1) impressions do not correspond to installs and
2) the algorithm from both stores supposedly take into account your ability to convert
visitors into users as a factor in determining keyword ranks. If your app listing
conversion is poorer than your competitors’, then your chances to succeed will be
limited.

In this article, we will explore a framework valuable for improving the conversion
rate of your app’s store listing. You might not always know what to begin with and
how to proceed, and this framework is here to provide you with the right steps to
success. This methodology, embodied by the CRO Loop (also described in [our ASO book](https://phiture.com/asostack/the-advanced-app-store-optimization-book-2018-edition-is-now-available-in-print-728e1bcd4754/)),
incorporates six stages.

![](https://miro.medium.com/max/3590/1*lQp_oLg0EgdqX3C1m6e5VQ.png)

_The CRO Loop used by the [ASO team at Phiture](https://phiture.com/app-store-optimization/)_

### **Step 1: Conduct research**

Research can take multiple forms. We generally divide ours into 3 categories: **
Looking Inward** (or, scrutinizing the App and its store presences), **Looking Outward**(
or, looking at some simple best practices, as well as looking at one’s direct competitors),
and finally, **Looking Skyward** (or, looking at phenomena separate from the app
stores). We’ll look these in detail here.

**1.1 Looking Inward**

#### _**Are your Value Propositions reflected in your store Assets?**_

It’s always good to evaluate whether your messaging is highlighting features or 
value propositions. A **feature** is something your app can do — e.g. counting calories…
A **value proposition**, however, deals with the benefit that your app provides 
to its users, e.g make tracking your diet easy. Sometimes a feature is a value proposition,
but it is always worth making sure that you’re clearly highlighting the advantage
of your app to its potential users.

![](https://miro.medium.com/max/2728/1*nyW827iHWTSjcKgr4VccWw.png)

_Notice the change in Uber’s titles from left to right. The titles on the right 
are a better reflection of Uber’s value propositions than those on the left._

#### _**User Testing**_

For ASO purposes, a common type of User Testing would involve asking a user to search
for a term that you know would include your app in the top 5 results (be careful
not to tell them which app you’re performing research for, in order to eliminate
as much bias as possible). Then ask them to comment on the first 5 results — what
they think the app’s function is, what they like or dislike, what stands out to 
them compared to the others, etc. The most valuable research will come out of doing
this in person, but a cheaper and simpler option is to do it online with one of 
the many available user research tools.

#### _**User Reviews**_

One will often find that an app’s users can summarise its benefits more easily than
the app’s marketers or even its creators. User reviews on any of the platforms can
prove to be a treasure trove of insights. In the image below (a workout companion
app), three of the top reviews mention how much they love the workout tracking feature,
and yet this feature is not mentioned once in the app’s store assets — icon, short
description or screenshots. User reviews should be constantly checked and monitored
to see how an app’s store presence can be optimised to include much-loved aspects
or address relevant concerns.

![](https://miro.medium.com/max/2478/1*GxRAC3HuTErushNb6tuYNA.png)

_The first three reviews all mention the tracking feature of the app as a standout
feature. Yet that is not reflected in the store assets themselves._

#### _**Popular Features**_

Your data should be able to tell you which of your app’s features are used more 
than others, and you should optimise your store assets accordingly. It stands to
reason that highlighting your most popular feature in your first or second screenshot
is going to do more for your conversion than tucking it away in your long description.
Your store assets are also a good way to test new features — if you strongly highlight
a brand new feature and your conversion rate increases, you know you’re onto something(
assuming you’re running a ‘clean test’ — more on that later).

![](https://miro.medium.com/max/3236/1*HG3XxFVMFtGRT1oXDRI9jA.png)

_Which of your app’s features are the most used? And to what extent are you promoting
those features in your assets?_

#### _**Popular ‘Content’**_

Let’s say you have a music streaming app available in multiple countries. You should
absolutely be looking at your analytics to see what most people are listening to
in each of your locales. Perhaps Metal is consumed far more than Pop in one of those
locales; it would be smart to reflect that content in your store listing. ‘Content’
doesn’t only mean music, pictures and video — you may have content even if your 
app doesn’t publish anything. A flight aggregator, for example, may show a holiday
background in its screenshots: if that background shows an African Savanna, but 
most holiday seekers are searching for flights to Thailand, then you may be missing
a trick.

![](https://miro.medium.com/max/4308/1*JpR75_OeoCWfUfdVjnxYGw.png)

_Sky Sports in the UK use their assets to focus on their most popular content (Football&
Live News) whereas the US version shows a larger variety of sports, with Formula
1 being just as important as Football._

#### _**Understanding your traffic sources**_

In 2019, I published an article about [understanding your Play Store traffic sources to ideate for experiments](https://asostack.com/multi-channel-traffic-impact-on-play-store-conversion-41f7e7a07f22).

#### _**The PET-ASO model**_

The Persuasion-Emotion-Trust Design model is a well-known and [freely available](http://www.humanfactors.com/downloads/Glossary_PET_design.pdf)
resource which looks at how to ‘sell’ something from multiple angles. These are 
easily applied to the App Store and Google Play Store, since we are, in essence,
selling the idea of an app to a store visitor (even if those apps are free). The
PET-ASO model — which is simply a variation of the traditional PET model, will be
covered in greater detail in a future post.

![](https://miro.medium.com/max/4720/1*Edx7f3FxoJgggXLOYS1Wig.png)

_The PET-ASO model — a variation of the traditional PET model applied to ASO by 
[Phiture](https://phiture.com/)_

**1.2 Looking Outward**

#### _**Best practices**_

 * **Legibility**

This is mostly applicable to screenshots captions. If you’re adding graphics or 
text to your screenshots, it’s important to remember that they’ll be viewed on a
small screen — even our largest smartphones and tablets are several times smaller
than the desktop monitors we usually design on. And the size of text is only one
part of the equation — font choice, contrast and letter spacing all play a role,
too.

 * **Icon**

A good icon must tick several boxes, but a good place to start is to include your
app’s name in the icon. Perhaps if you’re a massive brand, a logomark sans name 
may be recognisable to most store visitors, but for the vast majority of apps, adding
the name into the icon is a reliable way to build trust and increase conversion.

 * **Text Formatting**

Emojis can add a fresh twist to your short description. Likewise, using basic HTML
to bold text or change colours in your long description will create a valuable few
degrees of separation from an otherwise staid and dreary piece of the ASO puzzle.

![](https://miro.medium.com/max/4044/1*4YA_kf4BoOmOzPU6iaKVLA.png)

#### _**Competitor Intelligence**_

Regularly check up on your most direct competitors’ store presences. What are they
saying, how are they saying it — and why — are questions you should never stop asking.
Take a screen grab of their store presence every time they make a change, or enlist
the help of a tool such as Tune or AppFollow to track their changes over time. Keeping
abreast of competitor movements within the App Store and Google Play store can provide
valuable insights for your own App.

![](https://miro.medium.com/max/2588/1*L2xlrT0z-jZrCpwI4cAIEQ.png)

_Certain tools like Tune/AppFollow/SensorTower/AppAnnie allow you to track competitors
store changes, which may provide valuable insights into their research and strategy._

#### _**Market Intelligence**_

It’s important to remember that different locales will have different aesthetic 
trends, visual symbolism, religious attitudes, demographic breakdowns, and understanding
of things like emojis. If your app is a social media platform, for example, don’t
show profiles with British names in your Brazillian store. Or, using characters 
and mascots may go down a treat in Japan, but may backfire in another locale. Its
critical that as ASO practitioners, we stay abreast of these trends and make sure
that what we’re showing and saying in the app stores won’t come across as random,
misplaced, or — even worse — offensive.

![](https://miro.medium.com/max/4004/1*AxI5nKGw09h0KZ5tJzt0UQ.png)

_There are also certain visual styles and tones of voice which are specific to different
markets. For instance, mascots are widely used in Japan but are not that effective
in Western countries. Different countries and age groups also have different understandings
of the same [emojis](https://www.highspeedinternet.com/resources/emojis-the-universal-language-of-the-internet/)._

**1.3 Looking Skyward**

### **Blogs & External Resources**

Some of our favourite resources are listed below, but there are a whole host of 
others with freely shared insights from ASO experts.

 * [ASO Stack-Slack Group](https://phiture.com/asostack/aso-stack-slack-group-3757fc2aff0f/)
 * [AppTamin Blog](https://www.apptamin.com/blog/)
 * [AppFollow Blog](https://appfollow.io/blog)
 * [Apptweak Blog](https://www.apptweak.com/en/aso-blog)
 * [Incipia Blog](https://incipia.co/posts/)
 * …

### **The World Outside**

What is happening in current affairs which could influence how people perceive an
app’s store presence? What about politics? The environment? Something like GDPR 
and data privacy is an easy example in the wake of well-publicized account leaks
and data breaches, but there is a myriad of other influences which may have an effect.
Make sure you’re keeping up to date with developments and concerns in your app’s
field and beyond.

_Be careful of disingenuine promises or greenwashing._

![](https://miro.medium.com/max/4076/1*k6fEXuRiw7R6S3fQmD_4cQ.png)

_External factors undeniably shape marketing and therefore CRO efforts. Make sure
that you’re taking potential opportunities when they arise, as well as addressing
relevant concerns._

### **Step 2: Hypothesize**

After our research has concluded, it’s time to hypothesise for potential experiments.
A hypothesis is simply a statement or theory about what you think an experiment 
will do, and why you think it will do so. This is important because it ensures that
your experiments aren’t aimless and random.

A good hypothesis always satisfies three requirements.

 * It mentions a specific **action**.
    The **action** is what exactly you’re changing.
   For example: “Including Building Materials in the screenshots”
 * It mentions a specific **result**.
    The result is what you expect that action
   to have (and since we’re talking CRO, the result will likely be “Encourage Downloads”
   or “Increase Conversion”.
 * It mentions a specific **reason** and should lead back to your research.
    For
   example: “Because this app is designed for construction workers.”

So your hypothesis could look something like this:

![](https://miro.medium.com/max/3092/1*oYqeYBIfvaFxyfG50z862w.png)

You should absolutely approach your experiments as iteratively and selectively as
possible. If each subsequent experiment changes 5 variables, it will be very difficult
to pin down what element is responsible for any changes in your conversion rate.
Pick a single element to test in each experiment, and let the results inform your
next.

Sometimes an experiment may be a little more…well, experimental, and simply aims
to provide data rather than increase conversion. This is acceptable, so long as 
the learnings find their way back into subsequent hypotheses down the road.

_In August 2019, [we introduced a **new step to the framework after “Hypothesize”: Prioritization **](https://asostack.com/introducing-a-new-step-to-the-cro-loop-prioritization-566031430eeb)—
allowing you to focus on the high-impact experiments likely moving the needle and
avoid running the risk of being overloaded with poor quality ideas, as well as prioritizing
low efforts initiatives as time is often issue with prioritization._

### **Step 3: Brief**

A brief is a set of clear, simple instructions on how to transform the hypothesis
into an experiment. It can vary in terms of how detailed it is. It’s possible that
the person who performs the research and creates the hypotheses will not be the 
same person who crafts the experiment, and thus a clear brief ensures that any loss
of context will not affect the core of the experiment. Simply put, the brief is 
a set of clear, actionable steps for your designer or copywriter.

A brief for the previously mentioned hypothesis may look something like this:

_Format: Android Screenshots — 1080 px (w) x 1920 (h)_

_Please replace the current flat colour background with close up textures of brick(
first screenshots), wood (second screenshot) and cement (third screenshot). Please
ensure that each screenshot shows a current Android device. Brand guidelines to 
be consulted for font rules._

### **Step 4: Create assets**

This section highlight a few best practices and common techniques for visual and
textual experiments. This is by no means an exhaustive list.

### **Screenshot Caption Placement**

It may be tempting to eschew the norm of captions at the top of your screenshots
in order to differentiate your app from competitors who are doing just that, and
while it does add a certain visual interest, you risk sacrificing legibility when
users view your app from the product page, as some of the screen is usually cropped
off at the bottom.

![](https://miro.medium.com/max/4160/1*ZN8a4JkNsJYYQj7hxlhjZw.png)

_Changing the placement of the text on your screenshots may seem like a way to differentiate
yourself from the competitors, but you risk cutting off words and thus hinder communication_

### **Screenshot Order**

It’s statistically unlikely that potential users will scroll past the first few 
screenshots, so ensure that your most important features, value propositions and
content are visible in the first three screenshots. Placing any critical messaging
towards the back of your screenshot set is a reliable way to significantly decrease
the number of store visitors who will see it.

![](https://miro.medium.com/max/4080/1*5cfhXEFeUfsYfNfjwg1yAw.png)

_The first three screenshots are the most valuable. Data suggests that a tiny percentage
of potential users scroll past these first three. Make sure your most important 
information and value propositions are located here._

### **Connected Screenshots**

Connecting screenshots by using overlapping imagery, patterns or devices is a common
technique which aims to work around the unavoidable spaces between screenshots and
provide an impactful first impression. This technique is more suitable for the Google
Play store than on iOS because of the nature of Creative Sets testing (more on that
in step 5).

![](https://miro.medium.com/max/3792/1*VKKzA5B7EnxOHBKoTBk73g.png)

_Connecting your screenshots is a way of working around the divisions between your
images. Due to the nature of Apple Creative Sets testing, this is more useful on
Google Play._

### **Raised User Interface**

Raised UI is another very popular visual treatment which involves elevating UI elements
to give them the illusion of 3-dimensionality. This technique allows us to increase
the size of certain elements because it may free the UI from the traditional confines
of the device. Be aware, however, that overuse of this technique is rife, and unless
it is applied with restraint, it can actually create more visual clutter and noise,
rather than the intended effect of focussing the attention.

![](https://miro.medium.com/max/3608/1*802SZGftBoFfES_22JzRSg.png)

_Raised User Interface is a particular style of layering in which certain UI elements
are magnified and appear to hover above the background. It’s a good way to highlight
small but important UI or functions within the app._

### **Short Copy**

When it comes to the amount of copy, we believe shorter is better. Research shows
that our attention spans are minuscule when browsing on mobile devices — we have
fractions of a second to convince our users, and thus every superfluous word is 
a strike against you.

![](https://miro.medium.com/max/4360/1*_Yrge1EJiSmXG9k4qy8NnA.png)

_A good rule of thumb is to limit the number of words in your visual assets to 5
words or less._

On Google Play, brief and decisive short descriptions often show excellent results,
and a good rule of thumb for screenshot captions is 5 words or less per screenshot.

![](https://miro.medium.com/max/932/1*knOWYoIyGdCQNSoJQaTO6g.png)

One exception here would be when tone if voice or personality is critical to your
brand’s/app’s identity. Such an app might compromise brevity for brand cues or a
particular style if that is central to convincing users to download the app.

The same can be said for apps which are sub-culture-specific. If your app revolves
around meme humour and viral videos, then it’s worth using language which makes 
potential users feel that your app understands them, and is built for them.

### **Step 5–6: Test assets, Measure & Report**

#### **Before we start testing: set up an experiment backlog.**

This experiment backlog should be based on the research from the previous steps.
This backlog should allow to you plan and prioritize your tests, as well as to keep
track of experiments and learnings. Don’t forget in there to remind what your hypothesis
is (entailing your variable, expected outcome and rationale).

![](https://miro.medium.com/max/4024/1*CaNf0T6FiNh7hSJt34H6Uw.png)

### **Select your testing method**

It exists today four main testing alternatives:

 * **Google Play experiments:** native a/b testing within the Google Play store
 * **Creative set testing:** testing conversion of different screenshots on the 
   App Store via Apple Search Ads
 * **Sequential analysis: **updating your assets and measuring conversion before&
   after (also called B/A testing)
 * **Fake app stores:** landing pages with A/B testing, either your own or from 
   commercial solutions.

![](https://miro.medium.com/max/3522/1*IsqVk7e9uffcTEWa_q3KBg.png)

Some initial considerations for all testing methods:

 * Traffic should be divided equally between variations.
 * When possible, try keeping your marketing efforts consistent.

#### _**Google Play Store Listing Experiments**_

Google Play offers a [native experiment tool in the Google Play Console](https://developer.android.com/distribute/best-practices/grow/store-listing-experiments#best-practices),
which allows you to test your current listing assets against up to 3 variants. It’s
possible to test most assets including icon, descriptions, screenshots. The listing
has recently been revamped and presents new challenges in optimizing the assets.

![](https://miro.medium.com/max/3780/1*zw7SkkBVtx0YsxEM7e9yQA.png)

Indeed, the most visible an asset is, the most impact it’ll have. The feature banner
became a simple poster frame for the video and it no longer appears when not having
the video. As screenshots are now above-the-fold, ASO practitioners should consider
it as an optimization priority.

It’s considered the most attractive way of testing at the moment even though it 
has lots of drawbacks.

### **Pros**

 * Free and accessible to anyone publishing an Android app on Google Play
 * Native store UX
 * Up to 5 localized experiments at the same time
 * No need for technical resources or technical knowledge

### **Cons**

 * It calls out a winner with a 90% confidence interval while the 95% significance
   level, used to mean something is good enough to be believed, is the most commonly
   used.
 * No segmentation control.
 * Doesn’t differentiate the type of installs (_non-organic, organic, brand/non-
   brand searches…_) and therefore focus on aggregate conversion rate (CVR) as a
   go-to metric and inability to optimize for valuable users. This consideration
   is really well explained by [Gabe Kwakyi](https://medium.com/u/6827ce31c75c?source=post_page-----d1c4bc7ca725----------------------)(
   Incipia) in [this post](https://incipia.co/post/app-marketing/3-considerations-for-managing-aso-ab-testing/).

#### _**Apple Creative Sets**_

While Google Play Console has its own testing tool, this is not the case of App 
Store Connect. Since last May, you can, however, [test different creatives with the Search Ads](https://asostack.com/apple-secretly-launched-creative-testing-in-app-store-search-ads-761a9f7b8abb)
to understand their conversion rates on the App Store. This only allows you to test
your screenshots and app previews.

Only a couple of steps are needed to launch a test. First, you need to upload up
to 10 screenshots and 3 app previews -either in landscapes or portrait- to App Store
Connect. Beware that if you mix landscapes with portraits, the former will be flipped
so add them to the back.

![](https://miro.medium.com/max/3664/1*7r7O-xO69kVRKC4y2EEeTg.png)

_Screenshot 5 to 7 of [8fit](https://itunes.apple.com/us/app/8fit-workouts-meal-planner/id866617777?mt=8)
have most likely been used for creative testing_

Once done, connect to your Search Ads account and select the campaign or ad group
for which you want to add a creative set. Here are some hints to select the right
ad group :

![](https://miro.medium.com/max/1790/1*BxHNM6eHOdcjwJhY1ffH1Q.png)

 * It should get high impressions volumes to be able to collect enough data ;

 

 * _“High volume? Let’s select my brand ad group!”._ Well, I’d avoid this: you most
   likely rank #1 for your brand (see example of Avis), and only text ads display
   for searches in which you rank #1 organically and it’ll certainly don’t teach
   you much about the impact of your creatives.

 

 * Avoid ad groups with a strong bias, such as the ones targeting only one gender
   or a specific feature of your app. For example: assuming a food delivery app 
   wants to determine whether displaying pizzas on screenshots increases conversion,
   ad group with [pizza delivery] search term won’t be the right fit.

_Typically, competitor ad groups with a good blend of competitors are ideal. You
can also consider running the same test on different ad groups._

It’s pretty easy to set up new creative sets in Search Ads. The only thing you need
to keep in mind is that you can only select the screenshots and app previews in 
the order that they were uploaded in. You have to select these for all the device
resolutions that you’ve uploaded.

![](https://miro.medium.com/max/3200/0*QcRbQ-uQarhYcsj8)

_Creative set setup in Search Ads interface_

Want to know more about all the edge cases? Read this [comprehensive article](https://www.apptamin.com/blog/creative-sets-apple-search-ads/)
from AppTamin about creative sets best practices and optimization examples.

### **Pros**

 * Native store UX.
 * Segmentation control and therefore the possibility to get useful learnings to
   optimize for the best-performing ad group users.

### **Cons**

 * Costly. As it runs with ads, there is obviously the need for a certain budget.
 * Not true AB testing: Apple decides how much traffic it puts into each test and
   when.
 * Very limited: Only two elements can be tested (screenshots, app preview), in 
   search results only, in a predefined order, after they’ve been approved by Apple.

#### _**Sequential hypothesis testing**_

Let’s say now that you would like to evaluate the impact of a title change. Neither
Google Play Experiments nor Apple Creative Sets are solutions in this case. The 
sequential hypothesis testing, sometimes also called B/A testing (for **B**efore
and **A**fter) is the best method to evaluate the live impact of a change to your
store listing. Two considerations:

#1: Applying a change should lead to an immediate, noticeable uptick in conversion

#2: Calculate the uplift over 30 days before & after and see if it has statistical
significance

![](https://miro.medium.com/max/1728/1*UVEdANVYn6__UTypXGGu_A.png)

### **Pros**

 * Free
 * Native store UX
 * No need for technical resources or technical knowledge
 * Possible to “test” all elements editable by the developer (exclude for instance
   reviews)

### **Cons**

 * Well, it’s not really a test… Which means that it will be displayed to 100% of
   the users and that you don’t have a control group nor the ability to segment.
 * There is, furthermore, a high risk of decreasing your conversion rate (hence 
   impacting installs and paid acquisition campaigns).
 * Lastly, if you’re using this technique on the App Store, you’ll face a long rolling
   back time as there is the need for a new release to update your listing (besides
   for the promotional text).

### **Fake landing pages**

Alternatively, you can also test using a fake landing page.

To better understand what this is about, we will have a look at the example below
from Soundcloud. Users would click on an install button in Soundcloud website and
be redirected to a page imitating the real App Store, where 50% of the audience 
would see the default screenshot symphony, while the other 50% would see the test
version. When users clicked on “Get”, they were sent to the real App Store (where
they would have to click again on the install button).

![](https://miro.medium.com/max/2940/1*pXoDWbMf5iG42Z3y-lMnxQ.png)

Should you not have the resources to create this landing page internally, it exists
today two good commercial solutions offering this service: StoreMaven and SplitMetrics.

### **Pros**

 * Platform-agnostic
 * Ability to test everything (from app name to the impact of rating)
 * Pre-launch testing
 * Test new store layouts seen in betas
 * Track behaviour (time on page, screenshot clicks, scroll behaviour…)
 * Measure LTV instead of installs (with mobile measurement partners) and therefore
   the ability to craft messaging for potential best-performing users. This is especially
   useful for subscription-based apps or apps with in-app purchases.

### **Cons**

 * Costly: either because it requires some development time on your end, or because
   you pay a commercial solution.
 * Bad UX
 * Legalities: 1) Tracking without consent: you are tracking (in some cases even
   tracking whole heatmaps and clicks) these users in the tests. 2) Apple IP infringement
   of copying the look & feel of their app store exactly.
 * Priming affects your test
 * High drop-off (15–30%). First drop-off from users realizing they are in a test
   or not in the real app stores; and a second drop-off from users thinking that
   the app is loading in the background, who haven’t understood the need to click
   again on “Install” or “Get”.

### **Step 6: Measure & Report**

You need 3 criteria before declaring a test done. Consider the following questions:

 * Did you reach **statistical significance**? Google calls out winners when the
   confidence level is above 90%, but it should ideally be 95% or more (p-value 
   >0.05).
 * Are you sure the experiment has run long enough to even out? You want a representative
   sample, not a convenient sample. Sometimes Google calls out a winner too early…
   There might be little fluctuations throughout the week for a music app and users
   will likely be the same all week long, but that’s not the case for a productivity
   app which has two use cases (business during weekdays). Here at Phiture, we use
   our homemade Slack integration to monitor tests on a daily basis and make sure
   we’re not missing anything.
 * Did your experiment get enough installs? Conclusions shouldn’t be based on a 
   small sample size. It’s usually said that you should aim for at least 1000 installs
   per variation. SplitMetrics [explains](https://splitmetrics.com/blog/determining-sample-size-for-a-b-tests/)
   that it actually depends on the expected difference in conversion for all versions
   and on the current conversion rate. The lower both values are, the higher the
   sample will need to be.

Once your test is done, it’s time to report. When considering how to measure the
impact of your CRO efforts, the best numbers to consider are naturally ratios and
relative data points, as CRO is about improving your app’s efficiency. Defining 
the right metrics to evaluate the impact of your ASO actions could be an article
in itself, we will advise in this article to focus on the following ratios:

 * **Google Play**: First Installs / Store Listing Visitors
 * **App Store**: App Units / Impressions (Unique Devices)

It’s now time to use again your experiment backlog and to feed it with the results
of your experiments.

### **Conclusion**

Congrats, you’ve made it until the end! We’d like to give now you some final considerations.
There is no need to go through every step of the CRO loop before every experiment.
Instead, you should remember that testing is an iterative process and your next 
tests should be inferred from your learnings — either if a test win or loss. Let’s
say one of your Google Play experiment was a fantastic win in Australia, do not 
only consider testing it on the App Store but also in different locales.

 ** [The App Store Optimization CRO Loop](https://www.slideshare.net/Phiture/the-app-store-optimization-cro-loop)**
from **[Phiture](https://www.slideshare.net/Phiture)**