If a podcast with an ad insertion is downloaded, does that count as an ad impression? Getting to the bottom of the download vs impression debate is critical for marketers wanting to utilize audio advertising – which is why we explore it today.

Impressions and Downloads

Just over five years ago IAB defined the podcast measurement standards, which state:

• A podcast download is at least one minute of a podcast episode that is downloaded in one single day and filtered to exclude invalid and bot traffic.
• An impression is when a full ad has been downloaded in its entirety within the podcast download.

However, having a definition does not equal simplicity. The complex podcast world causes disparities in the data, and it is these disparities that are essential for marketers to understand.

Measurement Issues

Lemya Soltani, Next Broadcast Media’s Commercial Director says “The common issue we see among marketers not au fait with audio advertising is when brands look at download numbers or they try to directly compare the impressions to downloads. There will always be disparities for a few reasons. Firstly there is a multitude of devices, networks, and platforms all handling downloads differently. Furthermore, listeners consume podcasts in different ways. For example, a three-hour show may be consumed over multiple sessions whereas a 15 minutes show is more likely to be heard in one go.”

It is these factors that generate conflicting numbers, as demonstrated below:

• In one situation a listener consumes a podcast over two days and their podcast player downloads all the content in one go. This counts as one download. Whereas in situation two, (the only difference being the podcast player), the download occurs in chunks over the two listening days. This time two downloads are counted, as it happens over multiple days. 
• With regards to impressions. A listener tunes in and their player partially downloads a show including a mid-roll ad. But before they get to the ad, they stop listening. When the listener picks it back up later the same day the previously downloaded ad is discarded and a new ad is called and downloaded. In this situation, there is 1 download (as it is on the same day) and 2 impressions (as two ads were downloaded).

What about podcast streaming?

The common audio term used in audio is “streaming” but essentially streaming within podcasts doesn't truly exist. Unlike video, which is commonly streamed, podcasts are progressively downloaded at a user's or platform's request.

“While some big players use the term stream to measure played episodes – this typically means 60 seconds or more is played. But fundamentally the episode is still downloaded. To measure this, what we see is that the delivery of a 'streamed podcast' is logged the same way as a downloaded file in the server logs.” says Lemya.

However discrepancies here can also occur, an example being when new episodes of subscribed shows are automatically downloaded but not listened to until days, weeks, or months later.

When to use impression & when to use download

While downloads and impressions are linked, nuances in players and consumption mean brands should not rely on download information alone.

Lemya says, “There is well-verified data collected from millions of downloads by leading organizations that shows 15-25% of downloads start in the middle, and around 5% of downloaded podcasts aren't listened to. Therefore we suggest marketers do not focus on download information when it comes to planning and measuring DIA audio campaigns”.

The impression metric is a critical part of understanding reach for dynamically inserted ads in podcasts and also aids in frequency capping. Downloads on the other hand are more useful when trying to understand the popularity of a show for baked-in advertising strategies.

Lemya says “Just remember downloading does not always equal intent to listen”.