I can definitely see the value of comparing the performance of a current post against a post from a year ago if they’re on the same topic, for example. That would actually be really cool. Unfortunately, there really isn’t a way to isolate the reasons for the engagement those posts get. For example, in a year your blog could have a lot bigger reach, and you might get more comments and diggs and tweets on every post, so the engagement wouldn’t necessarily reflect your handling of a particular topic.

The Top Posts calculation isn’t quite that simplified or specific, nor is it specifically based on time frame, though that’s certainly the default assumption people make (myself included, initially, because it makes the most sense at a glance). The intent of the widget also isn’t really as a snapshot of recent posts. It certainly could be, but ideally it brings up content that’s a bit deeper than that and, ideally, gets readers into publishers’ archives.

It’s been really interesting seeing how people approach PostRank. We get the whole gamut, really, from folks who don’t care in the least how it works — they’re just happy to trust the algorithms and have less to read — to folks who want to completely dismantle and understand the entire system and who aren’t willing to trust anything. Sometimes they get comfortable with how we do things, sometimes not.

Really, though, the skeptics, like yourself, make the most interesting people to talk to. They often have perspectives and questions we haven’t seen before, which sparks great conversations and ideas about new ways to handle features. (So thank you!)

It’s certainly one of the motivations behind launching the Analytics Beta — to get input from people from all over the adoption spectrum.

Melanie Baker’s last blog post..A response on how PostRank works

I appreciate you stopping by and sharing some additional insight.

While I understand the explanation given, it doesn’t make PostRank a tool that I can use. Why would I want to know the PostRank of an old post at the time of publication? Surely it’s more valuable for me to know how a post I wrote a year ago, stacks up against a post I wrote this week, no?

Then, you flip the system with the widget. Now, you do look at how the post stacks up against the history of the site. Yet, the “Top Posts” are not really a definitive list but just a snapshot of recent published posts. What’s strange is that the “7.5″ appears to be calculated against posts published within a 2 week period–the exact same period that the 6.5 should have been calculated against.

It’s your system, and your algo, but I can tell you that with these apparent inconsistencies, you’re not going to get many folks feeling comfortable they understand what they heck they are looking at–I know I don’t understand it.

Actually, none of those examples are errors. (Whew!) I’ll try and explain what you’re actually seeing there.

In the first example you list, I can’t fully see the two dates those posts were published, but I suspect those two posts you reference were published quite a while apart? We don’t compare each new post to every post you’ve published that’s in our system, for a number of reasons, so comparing the PostRank scores and metrics of two posts published a year apart, for example, wouldn’t be applicable.

If the two posts you reference had been published in the same week, for example, the second one would definitely have gotten a higher PostRank score. However, the second example post, ranked 4.1 was published after a number of posts that had gotten even more engagement — more than 5 comments, 2 tweets, etc. When the post ranked 7.0 was published, however, the preceding posts weren’t getting as much engagement, so 4 comments was pretty good performance at that time.

Regarding the second example, the short answer is that PostRank scores in the widget and PostRank scores on the website are calculated slightly differently. A more in-depth explanation of that is here: http://blog.postrank.com/2009/01/07/postranks-website-vs-widget/.

Hope that helps clear things up. Any additional or outstanding questions, please feel free to give me a holler any time.

Melanie Baker’s last blog post..Feed Analytics Beta