We calculate your keyword ranking change scores by comparing the keyword ranking(s) on the first day of your date range to the ranking(s) on the last day of your date range.
Keyword Ranking Change Metrics Overview
This article covers how our keyword ranking change metrics are calculated. Ranking change metrics include:
Google Mobile Change
Google Local Change
These metrics are visible on your SEO > Rank Tracker dashboard, in reports, and on custom dashboards.
How ranking change scores are calculated for individual keywords
First up, it's important to understand how we calculate each keyword's ranking change.
Luckily, it's quite simple:
We compare the keyword's rank on the first day of your date range to its rank on the last day of your date range.
The difference in rankings is used for that keyword's "change" score.
Change scores can be positive (indicating an improvement) or negative (indicating the keyword has dropped to a lower position on the SERPs).
If your date range is one single day, we'll use the previous day's rank to calculate the change score.
For an example of how we calculate the change score, imagine your keyword "seo reseller program" is ranking 5th on Google on April 26, then climbs to 3rd place by April 30.
In this case, we give that keyword a Google Change score of +2, since it climbed by 2 positions between the start and end of your date range (April 26 - April 30).
You'll see this +2 Google ranking change as a green number in our interface (and if the change score is negative, it will show in red).
How change scores are calculated for all keywords
As well as seeing each keyword's individual ranking change, we show you an overall change for all keywords (or for groups of keywords if you're using tags or filters).
These overall change scores are shown in stat widgets above your keyword table.
We calculate these overall change scores by summing each keyword's individual change.
For example, imagine your tracking four keywords which each have a Bing Change score of -1, -1, +1, and -5 for your chosen date range. Summing each of those numbers gives an overall change score of -6.
This indicates that as a whole, all four keywords dropped by a total of -6 positions on the Bing SERP across your chosen date range.
Plotting change scores on charts
You can use line charts to plot ranking changes across time. This is possible for individual keywords, and for all keywords (or filtered groups).
Since change scores always compare rankings against the first day of your date range, you'll always see these charts starting from 0. From there, the line can move into the positive or negative.
The importance of date-based comparisons
It's important to point out that since we're using the first day of your date range to calculate each change score, the changes can be quite different depending on the start (and end) date of your date range.
For example, take the following screenshot:
This keyword has a Google Change score of 0 for the date range May 3rd to May 7th. It was at 4th position on both of those dates (so it hasn't changed).
However, if the date range was April 30th to May 7th, this keyword would have a change score of -1: The keyword was ranked 3rd on April 30th then dropped to 4th by May 7th.
This highlights the influence that date ranges can have on your change scores. Due to this, the change scores you see for one date range do not necessarily correlate with the change scores for a different date range.
Change scores and comparison metrics
As with most of our widgets, you can see a comparison against a previous period when viewing rankings changes. These comparisons are shown as small green or red percentages on widgets.
When looking at ranking change scores, the comparison percentage is showing how the current change compares to the previous period's change. So in this case, you're seeing a percent change of two different changes.
This may seem complex, so let's look at this example widget:
The date range for this widget is January 8 to 14, and you'll see Google Change is +433 for that date range.
The comparison period is January 1 to 7, and we're reporting that +433 is an increase of 337% compared to January 1 to 7.
Setting the date range to look back at January 1 to 7, you'll see the Google Change was +99:
+433 is 337% more than +99, which is why we're showing 337% as the comparison percentage. This is calculated with the following formula:
((date range value - comparison value) / comparison value) x 100
For the above example, the equation is ((337 - 99) / 99) x 100 = 337%
Note that you can have positive and negative comparison percentages, just like you can have positive and negative change scores.