The Visibility metric is the core SEO performance metric. It allows you to see, at a single glance, an accurate measurement of the overall visibility in Google of a group of keywords.
It is expressed as a percentage, representing your impression share in the organic results: how many times a user saw your website in the results page, from the total number of searches on the keywords.
To calculate the Visibility of a list of keywords, we take two parameters into account: your ranking and the monthly search volume, for each keyword. Depending on how high you rank, we estimate how many of the people searching for the keyword saw your website among the search results.
If you rank first on a keyword, you get a 100% impression share.
It is important to mention that when we say ranks, we also refer to what is known as "position 0", as defined by Google.
The impression rate decreases to 0% when you'd rank below the second page.
Anything in-between follows a rough estimate curve.
Then we multiply that by the average monthly search volumes and we get the impression share, which is the Visibility.
In the example below, it is easy to notice how the ranking of Keyword 1 is given much more weight in the combined Visibility figure, due to its relatively high search volume. Thus, it is able to pull the group's Visibility up to 83.3%:
For reasons of simplicity, the example above refers to a group of only 2 keywords. But, in practice, a group might contain hundreds, or even thousands of keywords, making it impossible to analyze the daily rank change for each of them. This is where the Visibility metric comes in handy: it shows you a figure representing the aggregation of all the ranks, weighted against their average search volumes. It is to a group what the rank is to a keyword.
Since it is updated every day (due to our daily rank crawls on both desktop and mobile) and since it can isolate the SEO performance, it allows the correlation with the various factors influencing the rank changes, like adjustments in Google's algorithms, on-page changes, etc. And in filtering out the search seasonality and trends, the Visibility metric guarantees an easy and accurate tracking of your SEO performance.
The Visibility metric is intended to be used as a reliable relative metric, when compared to itself in the past or itself for a competitor ("apples with apples"). It is not meant to be used as a precision metric, but monitoring its progression does provide an accurate, real-time picture of how well the website ranks in Google for a list of keywords.
Here's a short video about the Visibility Score: