I got bored today and took out the old spread sheet and tried to see if I could get some numerical support for some of the hunches I had with how well Klout and PeerIndex correlated with various Twitter metrics.
For the purposes of this test, I took the 50 accounts from the InfluencersinTravel.com list of independent travel influencers.
I then created a spreadsheet in Excel and imported the following data for all 50 people on the list:
- Klout Score
- PeerIndex Score
- Number of Tweets
- Number of Followers
- Number of people following
- Ratio of followers to following
- Number of Twitter lists
(4 of the 50 people did not have PeerIndex accounts or did not make their data public)
I then plotted the data for Klout and PeerIndex scores vs the various metrics and put a trendline on the data with a corresponding R^2 value. A value of 1.00 would be a perfect correlation.
Correlation with Followers
The most obvious thing you’d think would factor into a score would be the number of followers you have. Here is the data:

Correlation of Klout score with number of followers

Correlation of PeerIndex score with number of Twitter followers
PeerIndex scored correlate much more strongly than Klout scores with the number of followers you have. In fact, the correlation with Klout seems to be so low that it looks like Klout doesn’t even use it as a metic at all. The correlation between Klout score and followers was the lowest of anything I measured.
On one hand, I think that the size of your audience does in fact have something to do with your influence. After all, if you are only influential with 20 people, you aren’t really that influential.
On the other hand, there are many people on Twitter with inflated numbers of followers. This is usually done by auto-following whoever follows you. You can usually filter this out by looking at the followers/following ratio. That is what I looked at next:
Follower/Following Ratio
The key here to remember is that a high ratio means you have many more people following you than you are following.

Correlation of Klout score with ratio of followers/following

Correlation of PeerIndex score with ratio of followers/following
Again, there is almost no correlation with Klout scores with the ratio. It correlates slight more than with the number of followers you have, but not much. You can follow every spammer, bot and porn star and Klout doesn’t hold it against you. (Read about how one guy got a bot to get a Klout score over 60)
Number of people following
The next thing I checked is how score correlates with the number of people you follow. I wasn’t even sure I should do this because I’m sure neither company actually uses the number of people you follow as a positive metric. It would make no sense and would be very easy to game. I figured it would be a very small number for each service.
I was wrong:

Correlation of Klout score with the number of people you follow

Correlation between PeerIndex score and the number of people you follow
Wow. Klout correlates FAR more with the number of people you follow than the number of people who follow you!! Either there is something really messed up with the data set I used, or there is something really wrong with Klout.
PeerIndex score correlates less with following than it does with followers (which makes sense), but the difference isn’t that great and it is half that of Klout.
Twitter Lists
Next I checked Twitter lists. Someone who is influential you would think would be placed on Twitter lists more than someone without influence.

Correlation with Klout score and number of Twitter lists

Correlation of PeerIndex score and numer of Twitter lists
Both scores correlate high with Twitter lists, which is what you would expect. PeerIndex has a higher correlation, however. Almost 50% higher.
Tweets
Finally I looked at the thing which I suspected would correlate the highest: number of tweets. One thing that I don’t have data for is retweets. The closest thing which would approximate that with the data I had was the total number of tweets. If you assume an average number of retweets per tweet across all of Twitter, then it would make sense that total tweets would correlate with retweets.

Correlation of Klout score with total tweets

Correlation with PeerIndex score and total tweets
The correlation between Klout score and total tweets was the highest of anything I measured. It was 4x greater than the correlation with PeerIndex.
I have personally observed many people who stopped tweeting briefly because of a trip and saw a drop in their Klout score. I wasn’t surprised to see a high correlation.
Conclusion
If you want to increase your Klout score you should follow as many people as you can and tweet as much as possible. The person with the highest Klout score on this list has both the highest number of tweets and also follows the largest number of people. Both tweeting and following people are things which are under control of the user.
If you want to increase your PeerIndex score, get people to follow you and put you on Twitter lists. These things are not under the control of the user, so it would seem much harder to game PeerIndex. The person with the highest PeerIndex score had the largest number of follower, second most lists and the highest ratio.
While any measuring of “influence” is inherently subjective in terms of what you think determines influence, PeerIndex seems to me to be better than Klout if for no other reasons other than it correlates with things which make more sense in terms of influence. The highest factors that correlate with Klout score and factors which anyone can control themselves. This makes it open to gaming.
Notes
- All the data I used is available here on Google Docs.
- 4 people did not have PeerIndex data.
- One user had over 10x the number of followers than anyone else. It was such a larger outlier I removed the data point to see how much it effected overall correlation. Because it was only 1/50th of the datapoints, it had very little impact so I left the data point in.
- Klout also considers personal Facebook accounts in determining its score.
- PeerIndex considers Facebook, LinkedIn and other sites in determing its score.