Traffic Index is an estimate of the site's monthly organic traffic from the selected keyword set.
Traffic Index at a glance
Traffic Index is calculated similarly to Organic Visibility Score. The main difference is Organic Visibility Score only measures your ranking position, while Traffic Index also takes search volume into consideration.
Essentially, once we have calculated the Organic Visibility Score for each ranking position (which is analogous to the CTR), we will then multiply this number by the monthly search volume of the keyword, and sum all positions for a site.
Traffic Index is a cumulative metric, not an average (like Organic Visibility Score), so the final number will not be divided by the number of keywords. This means that Traffic Index is dependent on the number of keywords tracked in the set -- the more keywords are tracked, the larger the Traffic Index will be.
How it's calculated
We begin by calculating the estimated CTR for each ranking position. This CTR is determined by the site's organic ranking position for this keyword.
For example, keywords ranking at position #1 may receive around 25% of the clicks for this keyword, while keywords ranking at position #2 may receive a CTR of around 15%, and so on. Keywords ranking below position 10 will receive very few points, since the CTR for these positions will be very low.
Let's say we have a keyword set with 5 keywords at the following ranking positions:
Note that since it's possible for a site to rank for multiple positions with different URLs for the same keyword, each position (URL) will be counted, not just one-per-keyword. This is why in the above table we have two positions for "bluetooth speakers".
For each ranking position, let's use the ranking position to look up the expected CTR from the following table:
We can now see the estimated CTR for each keyword position:
Next, let's multiply the search volume by the CTR to get the Traffic Index for each position:
Finally we sum the Traffic Index for each position to get our final Traffic Index for the entire set:
Therefore the Traffic Index for this set is 435,315.
In the example above, there were only 5 keywords in the set, but if we added a 6th keyword, assuming the site had a ranking position for this keyword, the traffic index would be higher just because we added one more keyword.
Because of this, Traffic Index is highly dependent on the keywords that are in the set being measured. If the site is ranking for keywords that are not included in the set, the actual traffic may be lower than the traffic index shown in Dragon Metrics.
In Research, this is all the of the keywords this site is ranking for in our database. Every month, we track rankings of hundreds of millions of the most popular keywords. However, it's possible that many long tail terms may not be included in this database.
In Campaigns, this is the number of keywords you're tracking for this campaign. You're in control of which keywords are tracked, so the more keywords you add, the more accurate the traffic index will be. We recommend importing all of your ranking keywords from Google Search Console and Research to make sure this figure is as accurate as possible.