Analytics For iOS Games

Unlike a lot of console and PC games, most mobile and web games keep evolving over time [1]. It’s up to a game’s designers to ultimately decide how to change and improve the game, but the more data about players’ habits they have, the more informed a decision they’ll be able to make. Having good analytics on iOS games is simply essential these days.Recording particular events as part of the analytics is only part of it. The most important part is how that data is presented to the developer. Having tables with millions of entries does me no good, and as a busy indie developer, I can’t afford to spend hours writing scripts to analyze it. I want something that allows me to easily visualize the data and makes sense out of it at a glance.

One possible snagging point about analytics is that Apple was cracking down on some applications with analytics enabled a while back. Specifically, the iOS developer agreement states:

3.3.9 You and Your Applications may not collect user or device data without prior user consent, and then only to provide a service or function that is directly relevant to the use of the Application, or to serve advertising. You may not use analytics software in Your Application to collect and send device data to a third party.

Where does that leave us? Reading it carefully, it seems that the restrictions are limited to “user or device data”. I’m interpreting that to mean things like UDIDs and emails, not anonymous player usage data (how long did it take to reach level 5, how long are play sessions, etc), so I think we’re clear there.

The puzzling thing is that a lot (all?) of the third party analytics libraries do report device information, like what kind of hardware or iOS version is running. That is extremely important information that developers really benefit from knowing, but it seems to go against point 3.3.9. Maybe “device data” only applies to information about that specific device? (as in, the UDID that is now going away). I hope so.

Not having analytics isn’t really an option. Unless you make a game that you plan to throw on the App Store, never touch again, and hope for the best, you’re flying blind without analytics.

What are some of the options we have then?

Home brewed

If you read this blog regularly, you probably know that I’m a low-level, do-it-myself kind of guy, with a deep mistrust and suspicion of middleware. So you would think that I would want to write my own analytics package. After all, how hard can it be? Collect the data you want and ping your server with it. If you get fancy, you can even use a scalable server back end like AWS or GAE. Done.

Not so fast. To do that well, it’s a lot more involved than that. You want to batch when you send out the information, and you might want to distinguish between WiFi and 3G connection (to avoid causing extra data usage for players on a limited data plan).

That in itself is not even that bad. The real pain comes in visualizing that data, and that’s where you can easily sink in days or weeks, and you would still not have something as good as some of the other alternatives.

The other drawback is that if you have some successful applications, you may be generating Terabytes of data per day. Think about the storage and bandwidth costs for that. Yes, I know that sounds insane, but Playfish reported generating that much analytics data at a GDC 2011 talk (video for paid GDC Vault members).

Flurry

Flurry Analytics appears to be the most common analytics package out there among my indie iOS dev friends. It’s free and it’s easy to integrate. The visualization page is pretty good, and it even offers some fancy features beyond session length and events, such as flow through the application.

So what’s not to like? I was never able to make heads or tails of the application flow. When you get at that level, you start needing to spend some serious time making sense of data, which is what I don’t have as an indie. The web page to visualize the data is written in Flash, so for those of you using an iPad to check it, it’s not a good option. Update: Flurry apparently added a Flash-free web page since I last looked at it a few months back. Thanks Charilaos Kalogirou for the tip.

The killer deal for me was bloat. Adding the Flurry analytics library to an app increased the executable size by 500KB. I’m sorry, but that’s completely unacceptable for me. Memory is tight, and half a MB is very significant. I would rather add another large texture or another music track. And if you think about it, why does it need 500KB to buffer and send some events? That’s simply ridiculous.

Google Analytics

I never actually tried out Google Analytics. They have an iOS SDK and it integrates quite well into the web page Google Analytics environment. The main drawback I heard from other developers is that it’s designed more for web pages rather than for apps and games, so it wasn’t a perfect fit.

Anyone who used it want to expand on this in the comments?

Localytics

Localytics is a relative newcomer to the iOS analytics field, but it was love at first sight for me.

It has the same ease of integration of Flurry, and it provides very similar functionality. Localytics, however, is completely open source, so instead of a black box library, you get the source code and you can add it directly to your game. How much does it increase executable size? 4KB! You have to wonder what the other 496KB were for in the Flurry library.

As a bonus, their visualization web page works great on an iPad, although it can be a bit slow for very large data sets sometimes.

One of their biggest selling points is that they report the analytics in real time, but I really don’t care one way or another. Waiting 12 or 24 hours to see the analytics doesn’t bother me one bit.

Unlike Flurry, you can only add strings as parameters to events. That works fine if I have a set of discrete options. For example, when someone sends a bouquet in Flower Garden, I can send a “bouquet sent” event with a parameters that is “email”, “facebook”, or “sms”. As a result, I can see a nice pie chart with the breakdown of how people are sending bouquets. Very useful stuff!

But how about things that don’t have discrete options? For example, in Casey’s Contraptions, we wanted to see how long players take to solve each level. It turns out you can’t have a number as a parameter, but you can easily get around that by discretizing it yourself, which in the end, is easier to visualize. So when we send the LevelXXFinished event, we look at how long the player took to finish it, and we break it down into ranges: under 30s, 30s-1min, 1min-2min, etc.

This is what the report looks like for one of Casey’s Contraptions levels:

It looks like a fairly balanced level with the majority of the people spending under 3 minutes to solve it.

Random tips

A couple random things we learned along the way about analytics:

• Less is more. Start with just a few events and go from there. If you have tons of data, you might never have the time to look at it.
• Use analytics during playtesting. One thing is what people tell you, and another thing is what they really do. Since most of our playtesting is done remotely and we can’t observe as people play (which is invaluable), we can at least gather some hard data about it.
• Turn off analytics reporting in debug mode. Trust me on that one.

How about you? What’s your favorite analytics package and why?

[1] For example, Flower Garden has been on the App Store for almost two and a half years, and it has changed radically in that time!