• by Laurie Sullivan , Staff Writer @lauriesullivan, February 26, 2018

Worldwide mobile ad spend rose 33.6% to $142 billion, with $17 billion being spent on performance ads, according to a report released Monday.

The Adjust 2018 Mobile Benchmarks Report -- which analyzed trends in 2017 such as retention rates -- found that of the 11,000 available apps, 10.7 billion were installed, generating 1.29 trillion events.

Entertainment apps -- applications that allow users to search through videos and games -- do a good job of retaining users, at least on day one. After day one, these apps tend to fall steeply from 35% to 12% on day 14. Games, however, present the most fraud in apps -- about 34.65%.

Travel apps have a low retention rate from day one, but do not decline as sharply as other apps.

Utilities lose around 12% of users from day one to day 30. Ecommerce apps lose about 19% by day 30.

The analysis of the traffic from premium networks to these apps is fascinating. Those that engaged via Google’s network came back the most in 2017. In many cases user engagement rose over time, regardless of the source.

Twitter sits in the middle, with slightly more engagement than Facebook, although less than Google. The data also shows that Google comes out slightly ahead, with nine events performed per day per user on the final day of tracking compared with other networks. Facebook user interest is slightly higher initially, but drops more quickly.

Over time, Facebook users trigger fewer events at the end of the period. This means that Facebook might be a better source of users for apps that want to get the most out of their users quickly, while Google is a better long-term bet.

Google, the dominant player in 2017 for downloads, missed the mark when it came to retention. The study points out that iOS apps consistently retained more users than Android.

On the days after installation both platforms retained around 30% of users, but by day seven Android apps retained 16% of their user base, while iOS managed to keep 18% of theirs. By day 30, each had retained around 10% of their users.

Regionally, retention rates differ. Japan, the U.S. and Russia have retention rates similar to the comparison of iOS vs. Android. Russia and the U.S. closely align with the general OS trend, with 30% retention in the beginning of the cycle and between 10% and 15% at the end. Japan performed the highest, with 3% above the U.S. between day 3 and day 30. China has the lowest retention rate, with only 7% of users staying with an app by day seven.

In Europe (EMEA) apps tend to sit around a 29% retention rate, but by day 30 the rate shifts between 9% and 10%. On day 14, every country has a 13% retention rate. Their variance over 30 days rarely ranges more than 2%.