Consumers of all types are driving a mobile shopping transformation — evaluating, accepting, granting, sharing, opting-in and spending with brands that reach them in meaningful and relevant ways. Millennial and Gen Z shoppers are at the heart of this change — as mobile prodigies, they have never known a world without the smartphone. They are exchanging data and permissions for value and context every day.

One advertising format that’s delivering on the promise of younger consumers’ engagement is mobile video. To better understand how their mobile video ad experiences reflect their ideas, wants, wishes and needs, we worked with YPulse, a company that studies millennial and Gen Z consumers, to survey 1,000 shoppers between the ages of 13 and 36.

What we learned, in particular, is that mobile video ads work in some fairly specific ways and that the mobile experiences they expect change across age ranges. In total, we emerged from the survey with four key takeaways and nine major data points. The following list captures each of those.

Keep Video Ads Short And Sweet (Most Of The Time)

Nearly half the mobile prodigies in the survey emphasized ad length as crucial to their likelihood of engaging with mobile video creative units. Six-second video ads were the most attractive length for 48% of the respondents overall. Furthermore, on the younger end of the spectrum, more than half (54%) of Gen Z respondents said six-second video ads are the most engaging format. Conversely, older millennials, ages 30–36, appeared to be less concerned with brevity: Only 39% tagged the six-second format as crucial to capturing their attention.

Mobile advertisers can take advantage of the information these consumers are sharing by digging deep into data insights that help highlight the ages of their audience. For example, if an app is rich with older millennial downloaders — say, 30 years and older — then brands can probably bank on some latitude in the lengths of the video ads they create. Younger users, however, would suggest a strategy that keeps mobile video experiences short and sweet.

Mobile Prodigies Love Rewarded Video

Rewarded video is a growing sector, to put it mildly, as App Annie reports (in reality, it’s among the fastest-growing format out there). Within the format — chiefly found in mobile games, early on — the reward is an in-game prize delivered for each viewing. Gamers have responded with enthusiasm: Some 74% of them, according to a Tapjoy survey covered by , said the exchange makes the whole experience a positive in-game moment.  

Supporting the case for rewarded video’s importance to digital marketers, 46% of mobile prodigies in our survey said rewarded video is the most engaging mobile video ad format in their online worlds. Perhaps unsurprisingly, given gaming’s relationship with the unit, teenage male consumers are the strongest segment. More than half (58%) of male Gen Z respondents, ages 13–17, said rewarded video is their preferred creative unit.

One key aspect for brands interested in rewarded video is the evolving concept of where it works. While it got its start as a gaming-app feature, marketers are now seeing rewarded video bring powerful advertising outcomes to new environments. Pandora has had  with rewarded video, for example, and  are also finding traction in the rewarded-video space.

Elements Of Personalization And Control

It should come as no surprise that mobile video ads that are customized to audiences based on the personal data they grant to brands work especially well. One in four mobile prodigies told us that personalized mobile creative engages them the most.

They also want control to factor into their digital lives — that is, an additional 25% of the respondents we polled said they are most engaged by video ads that offer opt-in control.

These results reinforce the underlying integrity with which mobile marketers must always address consumers. Video or otherwise, every creative unit should match what digital consumers let us know about their location, movements and shopping histories, and they must also place the power to shape what they share, in terms of data, squarely in their hands.

Big Picture: Mobile Video Is Driving Growth

In all of this, we see the expansion of mobile revenue, advertising and video applications. Within just the past year, overall mobile revenue climbed 40% in 2017, , representing more than $21.7 billion. Furthermore, also according to IAB as reported by Forbes, mobile video ad revenue increased by 65%, representing some $2.6 billion, accounting for one-third of all the mobile revenue in play.

The approaches our respondents say work best are part of what is driving tangible business outcomes in the mobile advertising space. And they represent the future that these consumers are creating, choice by choice. Smart brands will plug into the data that mobile prodigies are offering and meet them in-app with video experiences that we now know prompt them to engage most often.

Julie Bernard is CMO at Verve.

This story first appeared at Forbes.