I often use a mix of the SEO weather tools and the SEO community chatter to determine if something is big is happening with a Google Update or not. There are times where the community chatter will be high and the tools will not fluctuate much and vice versa, but when both are showing fluctuations, I feel more confidence in my estimation on if I should do a blog post or not on the topic. Truth is, I've been covering Google updates well before these tools were out there, since 2003, all based on the SEO community chatter - and I strongly believe that is the best metric to measure these updates on a wider scale.
Google has been dropping hints that these tools are not always correct.
John Mueller said in a Google+ hangout last week, that he feels the SEO weather tools are "tracking things in a different way" than how Google would. He said this at the 4:40 minute mark into the video:
And I suspect maybe the SEO weather type tools out there are tracking things in a different way than we would look at it. So that's something where maybe something that overall doesn't really have a big effect is still picked up by them.
So I asked Gary Illyes from Google straight out about this on Twitter, "@methode do you think some of the SEO weather tools out there pick up on the wrong things?" and he responded "yes."
@rustybrick yes— Gary Illyes (@methode) January 18, 2016
Here is the video embed at the start time of John's comment:
I asked RankRanger, one of the SEO weather tracking tools for a comment on this and their spokesperson told me:
We are always on top of fluctuations, checking hourly and so it's highly unlikely that we would miss something. We see and log many structure changes and we can see that they have changed the semantic representation of html elements from the use of LI to DIV tags. We believe that the Core update covered more ‘real-time’ updates such as website changes of content and meta tags, we saw many cases that rankings were impacted within 24 hours. This is a shift for the more semantic presentation of the many search components they have released during the past year to enhance user experience (e.g., the variety of answer boxes, related questions,etc.).
Algoroo also responded saying:
SERP tracking tools are not in the business of tracking signals. They track the effect caused by Google changing how they order and display search results. But in a sense, I agree with John Mueller. I expected to see profound changes in Google's search results in the last couple of days considering how different the results were, but none of that happened. I'm seeing rather mild impact on things I care about. That said, Algoroo didn't lie to me... it simply reported on what it saw in the results. When the tool goes into orange or red, it really means that the results are very different from the previous day.
Some of the tools out there are quite sophisticated and able to slice into different verticals and geographic regions. While that's really cool, webmasters and SEO people should remember that these tools are simply an alert system.
Nothing we do will "decrypt" Google's search results and tell us more than what its representatives choose to share with us. My advice to everyone is to use Algoroo as an alert system and do their own investigation. If you received an alert from your website performance monitoring tool and it said your pages load 20% slower you wouldn't know why, but you'd be alerted of the fact and go find out if it's really the case and find the reason why.
Here is a quote from Accuranker:
AccuRanker Grump tracks almost 30.000 keywords across the world. The keywords has been selected at random, and are not tied to any exact industry. We watch the top 100 result of each keyword and compare it to the day before. All movements are recorded and an average is calculated.
When we see changes they always start in the US and moves to Europe and then Asia/Australia.
We believe that's their roll-out pattern indicating algorithm changes. Running a rank tracking business, we can also compare our Grump rating to the general changes across thousands of domains which shows big changes in those periods.
And here is Dr. Pete from Moz's thoughts on this.