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The Keys to Pursuing Reach in Podcasting’s Open Ecosystem

As podcasting matures, it continues adding metrics that advertisers have come to expect on other platforms. In 2021, there are more questions about reach and frequency than ever before, so let’s look at how they apply in podcasting.

The challenge of identifying audience

Reach defines the unique audience exposed to your campaign, and frequency tells us how many times that exposure happened. In podcasting, it’s important to understand that the unique audience is made up of households, not individuals. That’s because the only identifying information in podcasting is an IP address; no device IDs, IDFAs or similar personally identifiable information is passed from listening app to the publisher. 

The reason for this goes back to podcasting’s open ecosystem—the overwhelming majority of podcasts are available on nearly any listening platform. Shows from Stitcher’s Earwolf network are heard on Apple Podcasts, and fans of Spotify’s The Ringer network can listen on iHeartRadio—the publisher and player are entirely separate.

As a listener, even if your app requires a login, nothing that individually identifies you is shared. The IP is passed because that’s how the podcast server knows where to send the episode.

So, if IP addresses can’t identify an individual, how can we identify a household?

One answer is that the average household shares a single IP address assigned by its internet provider, and the household’s router shares it across all connected devices. That IP typically changes infrequently enough that it’s reliable for 30 days or more.

The role attribution partners play

That’s great for listening that happens at home, but what about podcasts consumed elsewhere?

This is where attribution partners come in. Simply put, podcast attribution vendors like Chartable, Claritas and Podsights have developed proprietary device graphs using multiple data sources to identify the devices belonging to a household, correlating them together. These graphs were developed specifically for podcasts and the medium’s unique challenges.

While the most common use of these platforms is to attribute online action—like web landings—for podcast ad exposure, their exposure data also allows us to understand the household reach and frequency of a campaign. With this in mind, the next question is often: What’s the optimal reach and frequency?

Reach and frequency are intrinsically tied. If you book a three-month campaign for a half-million downloads on a podcast that averages 100,000 downloads a month, you’re going to get a pretty high frequency, but a reach that’s limited by the size of that show’s audience. Book that same inventory across a dozen shows of the same size and you’ll see a lot more reach, but at a lower frequency.

Better reach = better conversion rates

Earlier this year, my colleagues Melissa Paris and Hadley Stork analyzed attribution data for 321 campaigns from July 2019 through December 2020, looking at reach and frequency compared to the conversion rates for web landings, based on unique exposed households.

They observed that campaigns with conversion rates above the median had, on average, four times the downloads and reach of campaigns with conversion rates below the median. The above-median campaigns also had an 8% lower frequency than those below the median.

Based on this, they concluded that reach seems to be a more important driver for web landing conversions than frequency. Simply put, increased investment and scale drives site visits in terms of both raw volume and in terms of greater efficiency. As reach increases, you are more likely to get a better conversion rate.

From a media planning perspective, the advice is clear: more investment pays off. But how to control that reach vs. frequency? The short answer is, right now you don’t need to worry much about frequency.

Overall, the average frequency for all these campaigns was 2.53, and the standard deviation was just 1.38. This suggests that podcast campaigns, in general, don’t vary widely in frequency, even while reach (and investment) does. That’s a good thing, because there’s no easy way to control for reach in a direct way, due to the medium’s open ecosystem. There’s just no straightforward way to judge a household’s previous ad exposure at the moment when an ad is served.

Many of the direct-to-consumer brands that have found success in podcasting are constantly searching for new shows. Effectively, they’re pursuing reach. My observation over the last seven years in the industry is that Stitcher and SXM Media podcast sellers work hard to assemble plans that maximize reach within clients’ target audiences. Our analysis shows this to be a winning strategy.