Advertisers

Measurement

Expert third party audience measurement

Podtrac Measurement of online shows and audio and video podcasts is the industry standard. Developed by measurement experts, and used by more publishers and creators that any other system, Podtrac Measurement provides intelligence and consistency in measuring online show audiences and ad delivery, and it is a system trusted by leading advertising brands and premium publishers since 2005.

Methodology for Podtrac’s Free Third Party Measurement Service

This provides a technical summary of the technology, process, and methodologies used by Podtrac for its free third party measurement services. Podtrac has developed its measurement methodologies with a team of professionals who have developed:

• Measurement systems used by most major digtal publishers and advertisers
• Internet data collection methods currently used by comScore
• advanced technologies for measuring Internet advertising effectiveness
• measurement systems for cable and digital television

Online Shows and Audio and Video Podcasts Defined

Podtrac defines online shows and audio and video podcasts as a recorded file or series of recorded files made available to Internet users through a distribution protocol known as Really Simple Syndication, or RSS. To be measured by Podtrac, media files must have an associated RSS feed. Individually recorded files, editions, or releases within a show are generally referred to as episodes.

Measurement Technology and Process

Podtrac is a complete measurement and reporting system, providing publishers and advertisers with information about thousands of online shows. The system begins with Podtrac providing the publisher a method for uniquely identifying the podcast so that Podtrac can collect data. The system continues with processing and categorizing collected data, and it finishes with analysis and reporting of the processed data.

Podtrac collects data using technology which encodes the "enclosure" XML of an RSS feed and the direct URL links on publisher websites. Whenever a listener or viewer downloads an episode via one of these encoding methods, Podtrac collects information about that transaction as an integral part of the fulfillment of the request for the actual episode file resident on the publisher's server. This operation is instantaneous and transparent to the end user.

Podtrac's measurement of media usage is at the lowest (most granular) level, the individual episode. This enables usage to be measured whenever it occurs. Once data is collected, it is then analyzed using Podtrac's proprietary nested analysis technologies. This provides advertisers and publishers with the most reliable data set for better understanding user activity on a per episode basis.

Data Collected by Podtrac

Podtrac gathers the following information about each Podtrac-encoded episode:

• The date and time of the request to start the download
• The source of the podcast download
• The unique show ID, as assigned by Podtrac collection technology
• Whether the request came through a URL or an RSS feed

Podtrac uses these data points, along with proprietary information about show episodes, series, and sources to summarize and aggregate usage.

Measurement Analysis Provided by Podtrac

Podtrac's analysis technology produces the following information on both a daily and monthly basis about each encoded online show:

Downloads

This is a measure of the number of times a specific episode file is requested during a given period of time. Downloads include file requests coming from RSS software, website directories, and publisher websites. The Downloads metric recognizes that, unlike some other media types, online shows can be enjoyed without the user waiting for the entire file to download. Therefore, if ads or sponsorship messages are placed near the beginning of an episode, users can be exposed to these messages without downloading or listening or watching the entire episode.

Unique Downloads

Unique Downloads is an unduplicated count of individually identified machines that began downloading a specific episode during a given analysis period. Podtrac defines Unique Downloads through a combination of cookies and algorithms based on IP address.

Download Source

Download Source is a measure of the client software used to download a podcast being counted, or the web site or server the user last accessed prior to downloading the episode.

Downloads by Country of Origin

Downloads by Country of Origin is a measure of Downloads for an online showoriginating from various countries during a given analysis period. Podtrac utilizes best of breed databases to infer country origination from download request data.

Limitations of the Data Collection and Analysis Methodology

Every measurement system has its limits, and Podtrac's is no exception. The Podtrac measurement methodology has the following limitations that should be considered by users of the data:

Downloads

• Downloads are tracked to specific computers through the use of proprietary methodology utilizing IP addresses, cookies, Internet directories, and specialized databases and algorithms. This methodology maintains the privacy and identity of the individual users that are downloading an episode.
• Podtrac measures requests for episodes from publisher servers. If aggregators bypasses publisher servers by caching content on their servers, these requests are not counted.
• Since online shows can be downloaded and stored, some percentage of downloads may not be played. Podtrac does not currently have a way to determine the exact number that fall into this category.

Unique Downloads

• Podtrac uses a proprietary method utilizing IP addresses, cookies, Internet directories, and specialized databases and algorithms to differentiate Unique IP addresses. IP addresses and cookies may not necessarily represent a single user, as more than one user may share a machine, or a user may download the same podcast from multiple machines.
• Since the Podtrac method uses cookies as part of the algorithm to identify unique users, an undetermined number of users may be incorrectly identified as unique because the user has deleted cookies. A survey from Jupiter Research found that as many as 39 percent of online users delete cookies from their primary computer each month: 12 percent delete monthly, 17 percent weekly, and 10 percent daily. The extent to which these numbers reflect the habits of listeners and viewers of online shows is unknown at this time. Additionally users who do not allow the use of cookies, or whose cookies have been lost because the computer was upgraded or browser-related software was reinstalled may be identified as unique, when they are actually returning downloaders. The extent to which either of these situations occurs cannot be determined by the Podtrac methods.
• IP addresses can change frequently, especially for mobile wireless users. To the extent that the same episode is downloaded multiple times through different IP addresses by the same user, Unique Downloads will be overstated.
• IP addresses are assigned by Internet Service Providers (ISPs). For large ISPs, IP addresses often bear little relationship to the actual location of the end user. All North American AOL users, for instance, appear to come from AOL headquarters in Virginia.
• Corporations with field-based personnel often provide remote connectivity through in-house proxies, so the IP address belongs to the corporate headquarters while the actual user could live and work somewhere else entirely.
• Some users may simultaneously use multiple modems, each with a different IP address, to accomplish the download. The occurrence of this is low, and expected to go lower as broadband high-speed access grows.

Download Source

Certain RSS software packages do not provide a referrer, in which case the client software being used cannot be identified.