BOSTON – Not that long ago, the biggest challenge with apps used to be getting people to download them. Now churn is “the single biggest problem in mobile,” according to Raj Aggarwal of Localytics.

The company uses machine learning and predictive analytics to help app publishers better understand their users via its software development kit, which collects data to create segments and audiences for driving desired behaviors.

“For example, if someone has abandoned a shopping cart and you want to try to give them an offer incentive, you can do that almost instantaneously,” Aggarwal says.

Localytics recently reported that while more people are using smartphones worldwide and downloading apps, 23% of users abandon an app after opening it only once. Knowing who those people are in advance is a key to success.

“We can automatically identify your users who are very likely to churn, so that you can start taking amore active, proactive aggressive approach at trying to maintain them,” Aggarwal, who is CEO of Localytics, says in an interview with Beet.TV. “We’ll give you the data to show what’s working and what’s not.”

Companies like ESPN, HBO, Nordstrom, CVS and Priceline know they need to be “best in breed” with their apps because it’s a competitive differentiator, according to Aggarwal, citing several Localytics clients.

“While people felt like a few years ago they were just experimenting with mobile, today their most valuable users and, in many cases, the majority of their digital users are engaging them through mobile devices and they can’t get it wrong,” Aggarwal says.

As the mobile space has developed, the most successful players in mobile usually win through apps and Aggarwal believes that will continue. But the challenges remain.

“It works differently than anything you’ve don in the past,” Aggarwal says of apps. “It’s fundamentally different from the web and people have to relearn how to acquire users, how to engage those users and monetize that user base.”

We interviewed him last month at the Progress Partners Connect conference. Our coverage of the conference is sponsored by Simpli.fi. More videos from the series can be found on this page.