What Is the Difference Between Unique and IAB Downloads?

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    Download: a unique file request that was downloaded. This includes complete file downloads as well as partial downloads in accordance with the rules described earlier. -IAB Measurement Specification v2

    What is the Difference Between the Unique Metric and the IAB Metric?

    A toggle in the upper right hand corner of your Libsyn Statistics Dashboard is available that allows you to choose between two views, one for Uniques and one for IAB.

    What are Uniques?

    The Unique download metric is an algorithm created by Libsyn for processing stats numbers. As we (as well as other industry parties) worked with the IAB (Interactive Advertising Bureau) on developing an industry standard for podcast stats calculations, we took some of those concepts and put them to work. In doing so, we developed a Unique Download metric that we have utilized since November, 2017.

    A unique download is a filtered statistic in which those requests are determined to be from the same overall download request, showing one unique download rather than the raw request count.

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

    IP Address

    User Agent

    If a request or group of requests (such as in a progressive download) comes from a single IP address using the same user agent inside a rolling 24 hour window, it is counted as a single unique download, rather than counting that as multiple downloads.

    The aim is to try to determine a single download from what may be several requests for the file from the listener, giving a more accurate representation of downloads rather than a less filtered overall download count.

    What is the IAB?

    IAB stands for Interactive Advertising Bureau. They have, with the help of companies like Libsyn and others, developed a series of standards that define a download. These standards include consistent filters and measurement practices that are particularly helpful in building advertiser confidence in the value of podcast advertising.

    Applying additional filters as per the IAB specifications to our existing Unique Downloads algorithm, we are able to further refine the metric. Additional filtering applied to the IAB certified metric include:

    -Applying IP address blacklists

    -Applying User Agent blacklists

    -Requiring the first minute of playable data is downloaded

    The IAB certified metric removes user agents that are known bots (good and bad) from the overall calculation, as well as downloads coming from IP addresses blacklisted for behavior not consistent with a website visitor or podcast listener (for example, a server caching content).

    Lastly, we ensure a certain amount of the file is downloaded for it to count. This makes sure the download is not counted if only the informational part of the file (such as the ID3 tag) was downloaded, rather than the ID3 tag and at least one minute worth of playable content.


    Q.When did Libsyn start processing stats using the IAB metrics algorithm?

    A.IAB metrics will go back to July 12, 2019.

    Q. Why offer both algorithms, instead of just the IAB metric or just the Unique metric?

    A. We have left the Uniques metric available as a default to make it easier to do comparisons and trend analysis. Keeping both allows you to determine how you want to use both of the numbers.

    Q.Which metric should I provide a potential sponsor?

    A. If you have an opportunity for sponsorship or an advertiser deck for your show; you can now say your reporting is 3rd party verified and IAB certified through Libsyn. In that instance, we would recommend reporting using your IAB certified metric.

    Q.Why are my IAB metrics lower than my Uniques metric?

    A.As explained above, the IAB metric provides further filtering on top of the Uniques metric algorithms. It is meant to filter more of the data, in an attempt to get even closer to a representation of listener counts per episode and across the show. This means the IAB metric will trend lower than the Uniques metric.

    I have more questions. Where can I find additional answers?

    If you have additional questions regarding your show and the stats that are calculated under either algorithm, reach out to our support team at support@libsyn.com.

    in Podcast ProducersStatistics
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