Do you have a second? How about 15, or 30, or 60?

That’s actually the question we most often hear from our advertising partners: how many seconds is best for an audio ad? We have a pretty good sense of the right answer, but thought it was time to make sure our perspectives and the actual results added up. So we partnered with audio analytics leader Veritonic to compare frequent radio listeners’ responses to 15-, 30-, and 60-second ads across the auto, financial, retail, and professional services industries.

The results? Significant… and substantiating our best practices. There’s no “one size fits all” answer, but in general, 30 seconds was the sweet spot. Ads that ran for 30 seconds outperformed others on most key performance indicators such as engagement, brand effect, and recall, and were also heard as more trustworthy, likable, and relevant.

More than two-thirds of respondents showed very similar responses to 30- and 60-second ads’ ability to make them think about how they can use a product or service, and also to deliver the right information they needed to consider buying a product or service. So, when choosing between a 30-and 60-second ad, it might make sense to boost creatives by investing in two 30-second ads rather than one 60-second spot.

Of course, the key is to get your audience to listen, ideally all the way through your ad. It’s like that proverbial tree in the forest – if you run an audio ad but no one hears it, did it really make a sound? Our study confirmed that those who listen through to the end of an ad show stronger recall and intent to purchase, and are significantly more likely to recommend the product or service. So part of the equation is ensuring that you tell a compelling story in just enough time to keep their attention and their recall.

Another key part is targeting the audience most likely to hear the whole story. We found that 61 percent of respondents listen to the full ad when it comes on. They’re the ones you want to capture. And 30 seconds seems to be the optimal point at which you can hold their attention enough that they feel they’ve learned something, they have just enough information to decide, and they feel compelled to use the product or service – but not so long that they zone out. As an interesting side note, we learned that, even more than traditional radio audiences, people who listen to both radio and podcasts seem to be the new superusers, and their reactions to ads were even more intense, so that’s a segment to consider closely.

Now, just like chocolate and vanilla ice cream, the best approaches do vary by industry and objective. In auto and financial services, 30-second ads did quite well, while in retail, success tended to come in at just 15 seconds. You might want to do a longer ad when explaining a new product, and shift to shorter ads when you’re well-known and want to gain frequency. But overall, when considering everything that you want to accomplish, that sweet spot still seems to be the 30-second ad.

So when you’re racing against the clock to hit the big time, we’re pleased to confirm that those 30-second audio ads are indeed the most likely to be in the right spot – at the right time.