The report, Does Every Second Count? Understanding New Video Ad Lengths, also found that so-called micro ads perform better when consumers are on the go versus when they are at home. Shorter ads also have a bigger impact on millennials compared to non-millennials. 

?Having sampled nearly 10,000 consumers, we?ve learned that micro-ads enjoy an advantage on smaller screens, where video ads dominate the entire screen real estate and where bite-sized content is the norm,? said Paul Neto, director of research at Yume. 

?We?ve also learned that millennials, having grown up with smart phones and being accustomed to short-form content, respond best to these micro ads, and, unlike older consumers, perceive them as being more enjoyable,? he said.  

?This is exciting, because marketers can now experiment with different length ads on different platforms and target the audiences they?re after in the most concise and effective way possible.?

The study found that short video ads can increase awareness, drive home key messages as well as convey brand imagery.

Video ads for five brands were tested: Charles Schwab, Hotwire, Jeep, Miller Lite and TV Land. Consumers were driven to content that matched their real-life consumption behaviors. Prior to the content, consumers were randomly shown a single pre-roll ad lasting five, 10, 15, 30 or more than 45 seconds.  

A key finding was that pairing short ads with short content does especially well on smartphones, outperforming in terms of ad recall compared to tablets and PCs. The benefit was seen for content between one and two minutes long. 

?When marketers are thinking about mobile, they should prioritize running ads where consumers are likely going to be watching short form content,? Mr. Neto said. ?When consumers are on mobile, short ads perform well alongside short length content.?

On-the-go consumers are more likely to recall short ads than are consumers who are at home for five-, 10- and 15-second ads. 

Millennials respond best to micro ads, with 20 percent of millennials recalling a five-second ad compared to 14 percent of non-millennials. Millennials also perceive shorter ads to be more enjoyable and of higher quality than non-millennials. 

However, the benefit of short ads is most pronounced for well-established brands. New brands typically need more time to communicate information. 

One way to use shorter ads is as a quick reminder for established brands to drive top-of-mind awareness.

Voiceovers seemed to boost ad recall for five-second ads compared to ads with music only.

The findings showed that even the shortest video ads can have an impact across devices, with 45 percent remembering an ad after just 5 seconds, compared with 51 percent for 10 seconds and 54 percent for 15 seconds. 

For an ad to be truly persuasive, noticeably impacting both brand favorability and purchase intent, a minimum of 15 seconds is needed, according to the findings. 

The findings underscore how content consumption habits are changing, which increased consumption of snack-sized content on mobile making shorter video ad formats more popular. 

With digital content consumption growing overall, marketers are investing in custom content created for digital platforms, including longer video ad formats. 

A key takeaway is that marketers need to develop a creative length strategy. 

?Based on our study?s findings, marketers would do well to develop a creative length strategy, diversifying their efforts and targeting different demographics according to their preferences and on the platforms of their choice,? Mr. Neto said. 

?We no longer live in a one-size-fits-all world when it comes to ads, and the appetite for different screens and different lengths gives marketers tremendous freedom to be creative and, as a result, more successful,? he said.  

?For example, short ads are great at driving top of mind awareness of a brand. But, if marketers are looking to drive persuasion metrics with a campaign, 15 seconds is the tipping point where we start to see movement. But, because of the nature of the device, we wouldn?t recommend running longer than 30 second ads on mobile.?