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How to Use the SEMrush Sensor to Detect Google Search Algorithm Updates

The SEMrush Sensor uses the daily rankings of millions of keywords to measure volatility in Google's search algorithm. This article will explain how the Sensor Score works and how it can be used to detect search changes that impact your website's traffic.
Pro Tip: To automatically stay on top of major Google algorithm changes, we recommend opting into SEMrush Sensor email notifications, which you can do here.

What is the SEMrush Sensor?

The SEMrush Sensor is a tool created by SEMrush to measure volatility in Google's search algorithm. The main driver of volatility in Google's search algorithm are the regular algorithm updates made by Google. Therefore, the SEMrush Sensor is an ideal tool for detecting changes to Google's search algorithm.

Here's a live view of the SEMrush Sensor with today's volatility score:

How can I use the Sensor to detect changes in Google's search algorithm?

Each day, SEMrush publishes a volatility score. The higher the score, the more volatility in Google's search results. In general, scores of 5 and above are considered high volatility, and suggest a Google search algorithm update. Here's a screenshot of SERP volatility for a 30 day period in August. We've highlighted the orange data point on the chart with a Sensor score of 6.2. Any score at this level is likely tied to an algorithm update.

SEMrush Sensor

When it detects a change, SEMrush shares any publicly known information about the algorithm change. To find the details about a specific algorithm change, you can look at the bottom of the report for a section that looks like this:

SEMrush Sensor Google Algorithm Updates past 30 days

It's important to keep in mind that Google makes changes to specific pieces of its algorithm, as well as general algorithm updates that impact all search results. SEMrush allows you to filter and compare specific subject categories, devices, and countries to identify more granular updates to Google's search algorithm. We recommend that you monitor the score specific to your website's industry and geography.

SEMrush's Sensor also publishes day-to-day changes in specific search engine result page (SERP) features:

  • Featured snippet
  • Local pack
  • Shopping results
  • Knowledge panel
  • Top stories
  • Instant answer
  • Top ads
  • No SERP Features

How is the Sensor score calculated?

To calculate the Sensor score, SEMrush records organic search results for a fixed basket of keywords at the beginning and end of each day. Here's a quote from SEMrush's website:

"For each keyword, we do a per-item comparison of "today’s" results vs "yesterday’s" results. We measure how much has changed in a day using Levenshtein distance (as a basis) and normalization. The total value of the score reflects the total search volatility for the day."

How can I use the Sensor to detect changes for my website?

If you have an SEMrush account, the SEMrush Sensor report will have a Personal Score tab that is linked to your website. If not, you can visit the page and enter your domain to see the Sensor score for your domain (note: you will still have to log-in and sign up for a free SEMrush trial to see a score).

SEMrush Sensor personal score

This report will calculate a daily volatility score specifically for your website based upon the keywords that you've uploaded to SEMrush. The more keywords you have in the system, the more accurate your score will be.

How else can I stay informed about Google search algorithm updates?

Other than the SEMrush Sensor, we recommend following the right accounts on Twitter. Industry experts and Google itself will often announce search algorithm changes. Here are the accounts we suggest starting with:

  • Danny Sullivan: Google's public @searchliaison: helping people better understand search & Google better hear public feedback. Also: tweets on technology, TV, sci-fi & more.
  • Google SearchLiaison: Official tweets from Google's public liaison of search, @dannysullivan, sharing insights on how Google search works.
  • Google Webmasters: News and resources from Google to help webmasters make great sites.
  • Search Engine Land: News & analysis on #SEO #PPC #Google #Bing & more.
Bruce Hogan

Bruce Hogan is Co-founder & CEO of SoftwarePundit, a technology research firm that provides advice, information, and tools to help businesses thrive. Bruce has experience investing at multi-billion dollar private equity firms, leading teams at venture-backed Internet companies, and launching new ventures. Bruce graduated summa cum laude from the Wharton School of Business.