When you review your download stats in Libsyn, you can look at the number of IAB downloads as well as the number of Unique downloads to gain a deeper understanding of how your show is doing. This article explains the differences between Unique and IAB downloads in terms of what they measure and how to quickly switch from one to the other and then back again.

Understand Download Stats

Counting how many of your show's episodes your audience downloaded is a key source of data for determining how well your show is doing. Having accurate download counts is important to build advertiser confidence and to dependably portray a show's popularity, both of which are crucial when trying to grow your podcast and revenue.

However, what counts as a download can vary depending on several factors. To offer a wide range of significant statistics, Libsyn measures episode downloads using two different definitions of a download: IAB downloads and Unique downloads.

What Is a Unique Download?

A "Unique" download refers to a set of metrics specifically developed by Libsyn. The metrics differentiate between raw requests for downloads and download requests from single users.

The Unique downloads algorithm accounts for two important pieces of information:

• IP Address
• User Agent (Apple Podcasts, Chrome, etc.)

If a request or group of requests (such as in a progressive download) comes from a single IP address using the same user agent during a fixed 24-hour calendar window, it is counted as a single Unique download.

What Is an IAB Download?

IAB is an acronym for the “Interactive Advertising Bureau” – an organization that (with the help of Libsyn and others) has developed a series of industry standards to define what counts as a download.

In addition to filters used by Libsyn's Unique download metrics, our IAB-certified metrics adhere to the IAB's 2.1 guidelines for calculating statistics. We use a fixed 24-hour calendar window to calculate unique listener sessions. Our definition of uniqueness relies on a combination of the user's IP address and their full User Agent string, while ensuring that at least one minute of playable content has been downloaded. For IPv6 addresses, we truncate them to the first 64 bits, while IPv4 addresses are kept in their entirety.

To ensure the accuracy of our statistics, we maintain a comprehensive IP exclusion list. This list primarily comprises known datacenter IP ranges from major cloud providers such as Cloudflare, Amazon Web Services (AWS), Google Cloud, and Microsoft Azure. By excluding traffic originating from these sources, we aim to filter out automated bots and non-human activity, providing a more precise representation of genuine human users. This list is regularly updated to account for new and changing datacenter ranges.

How Do I Compare my IAB Numbers with My Unique Numbers?

In general, IAB metrics filter out more downloads than the Unique metric. As explained above, IAB does not count downloads from bots or from other automated sources — such as servers caching content. For this main reason, you will normally see that you have fewer IAB downloads than Unique downloads.

How Do I Use My Download Stats for Advertising or Sponsorship Opportunities?

If you have an opportunity for sponsorship or for advertising on your show — congratulations! To describe your show's popularity, you can tell the sponsor or advertiser that your download reports are third-party certified by the IAB through Libsyn. Then, you should share your IAB numbers with the sponsor or advertiser.

What Do I Do If I Have More Questions About My Stats?

If you need more help thinking through your show and how your stats are calculated, reach out to our Support team at support@libsyn.com.

Switch Back and Forth from IAB to Unique

An IAB / Unique toggle appears in the following places:

• On the Dashboard at the top of the Stats Snapshot section
• On the Episode Details at the top of the Episode Stats section
• At the top of the Statistics page (which you can access if you are on the Basic Plan, or higher)

Click the toggle to switch between IAB and Unique.

If you're scrolling through the Statistics page to review your download stats and you don't remember if you set the toggle to IAB or Unique, just look to the right of the section title. If the text IAB appears next to the title, the stats are for IAB downloads. If a U appears, you're viewing Unique downloads. See the image below.