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How a simple dialog increased the sales of our Android app by 260%

March 28, 2011 at 8:08 pm | android, blog, monetizing | 12 comments


Short version. By introducing a dialog in our free application that encouraged the user to purchase the ad-free, paid version of it, we increased sales by 260% in the first week: 20% of the users clicked on the Go PRO button and, out of those, 15% finally bought our paid application.

Long version. We launched Spell Checker back in May 2010. It has been downloaded a million times (actually 985072, but come on, it sounds so much more cool), and has 60% active installs. It is ad-supported (by Admob, but it used to be Mobclix, see our experience with them here), and it doesn’t do too bad, with a eCPM of $0.09. The paid application is Spell Checker PRO, which is the same application, but without the ads. It used to be named Spell Checker Donate, in order to be very clear about the fact that there are no extra features.

It turns we need a user to click 70 times over our ads in our free version in order to generate more revenue than the paid one. We know this after doing a couple of operations over our Admob numbers. So, it is clear, we need to increase our conversion rate. (Still, we had a glance at our Flurry analytics, 18% of our users use our app more than 4 times a week. Not bad, but 40 clicks are way too many!)

What we did is dead simple: when you’ve used the application for 3 times, you get this dialog:

Go PRO dialog in Spell Checker

Go PRO dialog in Spell Checker

In order not to bother the user too much, we’ll wait until he has used it for 5 additional times before we show a similar dialog. Then, we’ll show it 8 times later, 13, 21, … (By the way, can you guess the next number in this sequence? :) ). The text will be slightly different each time, sort of like “So, do you like it now, or still not sure?”. Also, for existing users the message is a bit different.

While we analyzed this and other alternatives, we of course wanted to based our decision on numbers. Our estimate was that 2.5% of the active users would convert:

  • 50% of the users won’t even get to see the dialog in the first month. They are not active enough. This figure comes from our Flurry stats.
  • Out of the remaining half, 5% of them (1 out of 20) will hit the “Go PRO” button and buy it. This figure comes purely out of our air.

That sucks. We have no idea how many users will decide to buy it just because we suggest they do it. But now we know!

This pie chart shows the ratio of users that chose Free, 80%, versus those that decided to go PRO, 20%:

Users that choose PRO vs Free, from our Flurry stats

Users that choose PRO vs Free

We have matched the absolute numbers here with the actual revenue in Checkout, and it turns out that only 15% of them finally performed the purchase. That means, 3% of the users bought our application just because of our dialog. 3% is 15% of those 20%, and represents the magic ratio that we guessed out of air.

As a consequence, our daily revenue has grown by 260%, comparing the first week after we implemented this to the preceding weeks.

We are aware that the daily sales will considerably shrink after the dialog has reached most of the existing user base. So, of course this 260% won’t work for a new application. But it remains true that this has been the impact on our numbers, and hopefully all this helps you in your own estimates, which is our main objective with this post. Social behavior is so unpredictable!

We are just starting out in this fascinating world, and are aware that we are not good at selling. So help us a bit: how would you suggest we increase our conversion rate?



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