In podcasting, we often don’t have access to actual playback metrics from the browsers/phone-apps that listeners are using. Instead, there are industry standard metrics used to measure things (like “Downloads” and “Listeners”). These come from the Interactive Advertising Bureau's Podcast Measurement Guidelines.
Good news, Dovetail is IAB 2.1 Certified! Here are some of the ways we measure things.
Listeners
When you download a podcast MP3 from Dovetail, your computer/phone sends what is known as a “User Agent” string identifying that device (phone app, browser, etc). This might be something like “Safari on iOS” or “PocketCasts on Android”.
We combine this with your IP address - which comes from your WIFI network or cell tower. This identifies you as a unique “Listener” to us. If there is a change to your WIFI network or cell tower, you are considered a different Listener.
Additionally, if your ISP gives you a newer IPv6 address, they may change more quickly over time even if you didn’t change WIFI/cell. It turns out those are less static than IPv4. In this case we use only the leftmost half (64 bits) of the address as recommended by the IAB. This gives a more accurate count of unique Listeners.
Downloads
Typically, a podcast MP3 will look something like:
When your app/browser requests this episode from Dovetail, we begin sending its contents from left to right. Once you’ve requested at least 1 minute of audio not including the upfront metadata/image, that counts as a “Download”.
Every Listener may only Download an episode once per UTC day. Any subsequent requests form some/all of that episode on the same UTC day are duplicates, and don’t count towards our metrics.
If a listener is playing/pausing, their device may make several requests for different chunks of the episode. In these cases we discount any duplicate/overlapping parts of the episode you’ve requested, and apply the same 1-minute rule. For example, if you request 59 seconds of segment 1, and then re-request 30 seconds inside that same 59 seconds… that is not a Download. Request 1 more second after that, and you’ve got yourself a Download.
Impressions
Episode MP3s served by Dovetail contain both audio uploaded by the producer, and pre/mid/post roll advertisements. Using the same example as before:
If your device requests the entire preroll, that counts as an “Impression” on that ad. These ad Impressions determine when we can count/bill an advertiser because we, a listener, received their ad audio.
If your device only requests 90% of the preroll, that does not count as an Impression. The entirety of the ad must be requested to count.
Invalid Traffic
In some cases, Dovetail receives requests that are not valid traffic. Some common cases include:
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- Websites that preload MP3 audio as soon as your browser navigates to them. Without waiting for the user to click “play”.
- Bots that scrape/request many episodes from Dovetail
- Legitimate looking devices behaving in non-human manner (downloading 1000s of the same episodes day after day, etc)
PRX actively makes an effort to find/identify/filter this traffic, routinely auditing Dovetail traffic. If it turns out to be your own website/application misbehaving, we will attempt to contact you to fix the issue. In all cases, we may decide to filter Downloads/Impressions coming from these sources if we cannot remedy the problem.
If you have any further questions - reach out to podcast-support@prx.org!