Sonibyte Podcasting Blog

Podcast Length--Does a Podcast's length affect its popularity?

Does the length of a Podcast affect its popularity?  It is possible that it could be better either to create shorter episodes (more to the point, snappier) or longer episodes (more complete, serious, and more value per effort to download).  It is also popular that being "at the mean" would be best (reliable length, consistent).

We have shown in an earlier post that Sonibyte's Podcasts have a long "tail" of downloads.  However, it seemed to reasonable to use the number of downloads a Podcast receives over the first three days after it is published as a proxy for its ultimate popularity.

We compared this figure for about 1,600 Podcasts against their length in words and found a mild positive correlation (longer length = more downloads):

As you can see, the chart is pretty messy and somewhat unconvincing.  The 0.25 r-squared figure on the chart indicates that 25% of Podcast popularity could be attributed to how many words are in an episode.  However, there is a LOT of scatter on this diagram.

There is a region of Podcasts with high downloads that have only a middle range of words (the cloud of dots that reaches up in the middle of the chart).  There is also a group of high-word-count Podcasts, that extend across the chart in almost a horizontal, low-download-count line.

We look at this download vs length analysis for a few individual feeds.  Here is the result for the "Weekly column" feed one that we also studied in our last post:

The correlation here is poor, and if there is any slope to the line, it may be negative (i.e., longer episodes do worse).  We looked at other examples, for a variety of Podcast types.  They all showed a similarly poor correlation within the episodes from a particular feed between length in words and the number of downloads.

The data above supports some suggestions regarding optimizing the length of a Podcast:

1.  Longer podcasts may be somewhat more popular than short ones.  One explanation for this is that they give the user a better return on the effor of subscribing and downloading each episode.

2.  Podcasts with between 800 and 2400 words seem to generate the best levels of downloads.  Very few of the feeds that were longer or shorter than this, did as well.

3.  There is no benefit or cost to make any particular episode of an established Podcast feed longer or shorter than the average length for that feed.  There is no reason to pad or edit existing text, before converting it into a Podcast.

We have used the data from our partners to see if publishers should worry about the length of their Podcasts.  Our overall conclusion is that they should probably worry more about the quality of their content and which topics they focus on, than on how long their episodes last.

There is one final business point to consider.  More Podcasts are starting to carry advertising (see our recent announcement regarding our new dynamic ad insertion feature).  A twelve minute Podcast can carry three or four fifteen second ads, while a three minute Podcast could probably only carry one or two.  We predict that this factor may drive many publishers towards longer formats, in the future.

Podcast Length--Does length vary between Podcast types?

Our last post showed a wide range of Podcast lengths.  The peak in the distribution was around 1,200 words, but some Podcasts were much shorter and some much longer.

When we examine Sonibyte's data by feed, we find that our feeds divide into three groups.  A group of shorter posts that are mostly quick tips and comments peaks at around 600 words.  Feeds that are based on weekly columns and stories center around 1,200 words.  Commentaries, reviews, and opinions seem to stretch over longer time periods, and peak at 2,000 words.  Here are charts showing the distribution of lengths for one feed from each of these categories:

 

 

Notice that the Tips and Comments type of material sometimes "runs long."  A subscriber for these feeds will sometimes find that a normal three to five minute Podcast is stretching out to 10 or 20 minutes.  However, most of the feeds in this category are personality-driven--often with the writer doing his or her own voiceover conversion.  Most subscribers to this type of feed should welcome a few more words on a particular topic, from someone they feel they know and like.

The column-driven and commentary-driven Podcasts are more closely tied to the corresponding types of print articles.  Weekly columns tend to have a rigid length limit, and are not allowed by the publisher to vary much from their target length.  Commentaries, interviews, and other longer articles also tend to have a pre-specified length.

To keep subscribers happy, publishers should probably set upper and lower limits on the number of words in each feed.  Most writers will stay within those limits as part of their normal editing cycle.  If a writer has ocassional longer articles, a publisher might consider making those into a separate Podcast--perhaps with a related title (to make it easy for subscribers to find).  This separation will keep listeners from having to adjust their time schedules to suit the length of the publisher's feed.