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May 4th Google Core Update Analysis

May 4th Google Core Update Analysis

Inside this article:

At the beginning of May, SEOs got hit with another major Google update. Major, as it impacted a lot of sites. And since you’re reading this, I assume you experienced some changes in search results yourself.

There’s no point in quoting web page owners who complain about losing 90% of their traffic or bragging about their new high positions in Google. After all, there is nothing actionable in this.

SERPs volatility? We know that the update is a fact and as of today, we can see that it settled down already, even Google confirmed that on May 18.

In this article, I will show you why this update is not just about big authority sites. 

Take this for example: health and law niches have seen an opposite impact on SERPs. Small pages have had some wins here and there and for some categories, they are ranking better than before the update. 

Grab a coffee, sit comfortably, and read the full story.

No fluff, no conspiracy theories, and no guessing game—I will share the data, and you decide what happened... With a tiny bit of my commentary that I believe will be helpful for you to draw conclusions for your sites.

Let’s dive into Surfer’s world of on-site factors, keywords, and domain characteristics to find out what happened. 

Data sample and methodology

I extracted a list of keywords from two periods: they were analyzed on April 22 and reanalyzed on May 8, and 11.

To understand the impact of the algorithm update, I’ll look into data from Surfer. The same keywords and locations, before and after.

I started the analysis with 1060 keywords analyzed in April and twice in May. That means over 30k successful page crawls. Each SERP was fully crawled so no missing or incomplete data were analyzed.

Results from May 8 and 11 (the post-update era results) were really close to each other. Data showed no significant differences between them. 

Each keyword was analyzed against multiple factors like:

  • domain organic traffic
  • referring domains
  • exact keywords density
  • partial keywords
  • keywords in title and H1
  • page speed metrics
  • wordcount

To figure out what is what, I created a massive file with all the factors I mentioned above. This is how it looks like:

Looks like complete chaos, but these numbers are in fact well structured with following factors and segments


Traffic and backlinks in SERPs

Can we call it an authority update? On the chart below, I checked how much more traffic and backlinks pages in the top 10 have. Over 10% more organic traffic for domains that are in the SERPs now does not sound scary, we have to get into details.  See traffic and backlinks change compared:

Average traffic and backlinks grew after the update

From this chart, you can clearly see that after the update, SERPs are populated by pages with more backlinks (by 35%) and more traffic (by 14%). 

Preparing the data

With the analysis we want to figure out what happened in the SERPs and how they changed based on different ranking factors.

To simplify it a little bit, I grouped pages in three buckets:

  • pages that lost position in the top 10 are called losers
  • pages that appeared in the top 10 in May are called winners
  • pages that remained the storm and they are still in the top 10 called survivors

This approach gives a better understanding of what happened. 

Initial thoughts

Pages that recorded the biggest wins have more trust in general. That means, they are bigger, they have more traffic, and more backlinks than survivors and losers.


From the chart we see that winners (pages that showed in SERPs’ top 10 for the first time) are pages with almost 100% more organic traffic and 60% more backlinks than losers, who were outranked.

Survivors (pages which were in the top 10 before and after the update), have a little bit more traffic and less backlinks than losers though. 

Narrowing the data down again

Big pages are winners—this is the most common conclusion of the SEOs. This may be a good overall conclusion but it is not always true. Let’s dig deeper!

Did big pages wipe out smaller niche sites completely? 

The chart below shows that there are plenty of keywords with small pages kicking authority sites’ asses. 

The update is not as simple as authority pages win or it is applied just to specific keywords or categories.


Not that many keywords affected as we all expected, huh?

How do I know that and why is that so important?

I checked all the keywords if winners had more or less traffic than losers. If they had more - keyword landed in the red bucket, if less - blue. This way I managed to isolate authority leveraged keywords and analyze both groups separately. 

Let’s find out which keywords got more authority pages in search results, and what are the main reasons for that. And on the other hand, when niche websites were winners.

Authority leveraged keywords

For this analysis, I extracted a specific group of keywords: for those, winners had more authority than losers on average. 

Take a look at the distribution of domain traffic and backlinks on the charts below:


As you can see, in this group there’s a huge disproportion between winners and the rest. 6x more traffic and over 4x more backlinks on average is hard to beat. 55% of all analyzed keywords are affected by the leveraged authority factor.

On-page factor #1: Exact keyword density in body

Now it’s time for you to decide if on-page changes were a cause or an output of the algorithm change.

On the chart below, I analyzed exact keyword density in the whole body for all the three groups. Remember that right now we look into SERPs that were populated by authority pages after the update.

Losers and winners’ keywords usage is very similar, but when you look at survivors, their density is much lower.

Losers and winners tend to have nearly 70% higher exact keywords density in the body.

Survivors were small to mid-sized pages with much lower exact keyword density.

On-page factor #2: Exact keyword in H1

Next, I checked if the exact keyword appears in the H1 of the page.

Winners do not precisely target keywords they rank for—they used exact keywords in the title less than other pages. Survivors are slightly better than losers in this area. 


On-page factor #3: Partial keywords in body

Partial keywords begin with the same 3 letters as any word from search term. 

When it comes to their usage, new pages have 10% fewer partial keywords on average than lost. The difference is less significant but it’s still worth noting this fact.

You will see why in a few moments. 


The best chance to survive for a small page is to have lower exact keywords density in body and optimized H1 and title. Some small pages might have tried too hard with exact keyword stuffing—that could be the trigger for a page to be replaced with an authority one. A page that didn’t try to “trick” Google and that may have more trust. 

On-page factor #4: Content length

Winners’ pages are 10% shorter on average than lost and survivors. But it does not look like a game-changer. 

As domains are of high authority, they don't have to provide the most comprehensive content, but it can be an effect not cause.

On-Page factor #5: Page speed

PageSpeed? Nothing significant. New pages were slightly faster in TTFB but also slower in overall load time. There’s no point in pasting a chart here since the differences are not noticeable.

It looks like big sites have better techies, but they may load a bit slower as they are... bigger. Nothing to do here.
My overall conclusion is this: If you are small and affected negatively by the update—try reducing exact keywords density and raise partials to the level of your competitors. Optimization with true density will be beneficial. Your long-term goals should be raising authority for the domain. You can start with missing common backlinks against small pages that won. 

Dethroned authority websites (yes, there are a lot of them!)

David can beat Goliath again. This sample proves that there are many keywords where authority pages were dethroned by those with less traffic and links.

45% of all analyzed keywords are in the group of websites, which besides smaller authority than previously ranking pages, managed to crack the top 10. 

Now here’s the interesting part. Despite everyone raving about the “authority update”, for almost half of all keywords this is not true. Let’s dive in.

Reversed update logic!?

For those keywords, there were only 43 cases (less than 10%) when the winner had more authority than a survivor. Based on that we can assume that content had a lot more impact on the ranking than domain strength.

It's worth pointing out that survivors had 40% less traffic than losers. When we compare losers to winners, the difference is tremendous, winners had 10x less traffic on average and still won a position in the top 10! 

On-page factor #1: Keyword density in body

We can observe a slightly different situation in exact keywords. Survivors still have lower keyword density, but winners have 10% higher density than pages that losers!

On-page factor #2: Exact keyword in H1

Keywords usage in H1 in the title confirms optimization issues on pages that lost rankings.

Opposite trend again


Looks like when small pages win, they win with well-optimized content targeting keywords precisely in body, title, and H1 content. It could be related to the quality of information, not just optimized content, and a potential revert of what happened in the past. 
If you are affected with the drop—reverse engineer small pages that won rankings. These are the best candidates to examine and follow.


On-page factor #3: Partial keywords in body

Partial keywords are also used more frequently on winning pages. 

According to the chart, pages that outranked previously ranking pages use partial keywords a bit more often. Is the difference significant? I’ll leave it for you to judge. 

On-page factors #4 and #5: Page speed and length

Both metrics showed nothing worth mentioning here so I will skip them.

When does authority matter?

Now that we have a better overview of what happened in SERPs after the major update, let’s move on to the practical side.

There are groups of keywords treated differently with almost precisely opposite characteristics. Is there any connection between authority or niche sites winning the keyword? I wish I knew for sure... but! 

Update has an impact on categories

I wanted to know if there is anything common for keywords that got hit either way. 

Keywords categorization helped. All keywords in Surfer’s database have a category assigned to them. 

Want an example? Categories assigned to the “assault defense attorney” keyword are Law & Government/Legal/Criminal Law. Looks legit. 

I took categories of keywords in both groups and then checked how many times each category appears in the bucket divided by the number of categorized keywords in the group. 

I used slightly wider terms to describe categories like law, finance, or health to get a better overview. 

Here is what I found:


This is what I want you to remember from the article


The chart presents the impact on specific categories. 

Values above 0 got hit with leveraged authority factors. Values above 0,5 mean really strong impact. There are +200% more keywords where strong domains replaced niche sites (travel, real estate, vehicles).

If the value is close to 0, that means there’s a balance of keywords in particular categories won with authority or by the smaller niche sites, however, authority leverage seems to be a trend overall.

All below 0 looks like a reversed authority factor. In these categories, Google ranked more domains with lower organic traffic compared to pre-update analysis. Well, I am surprised to see health, family, beauty and law and food here.

Now this is critical. As with any data, segmentation is key. And that’s why before we call the May update “authority update”, we need to analyze the category of a keyword.

If you’re operating in a health, beauty, or law niche, there’s a chance your niche, topically relevant website was pushed to the top ten dethroning some high-traffic domains.

Some other key insights from my side:

  • There are 2x more uncategorized keywords in the “niche sites win” group (where low authority domains outranked high authority sites). For me, it appears as an update affecting popular keywords that Google can clearly understand and categorize. Uncategorized keywords are basically keywords that can’t be found in Google Keywords Planner.
  • Update impact on specific categories varies a lot. Some niches got even reversed effects, like health and beauty. 
  • Affiliate keywords (best & review) were 30% more frequently appearing in the authority leveraged keywords sample. For those industries, building links will be probably the first step to recover.
  • Search volume and keyword length show no correlation with landing in an authority win or niche site win bucket. Both buckets are nearly identical in search volume of keywords. By keyword length I mean average characters and word count of keywords in both buckets. Almost the same values. 


(Biased) summary

May Google Core Update leverage authority in niches that survived EAT, YMYL, and following updates that involved reputation. It appears that Google tries to reward authority and trust in more areas. 

There is also a bit more space for smaller sites.

Surprisingly, the May changes gave new opportunities for industries where high authority sites were recently a must-have, like health and beauty.

Of course, authority is still required to rank there, but many pages managed to outrank big brands. Apparently, being “big” is not enough to rank for those. Relevancy is a winner!

Special thanks go to Constantin Oesterling, Rob Ulejczyk, Bartłomiej Korpus, Lucjan Suski, Karolina Gawron, Sławek Czajkowski, and Matt Diggity. This analysis would be much harder or almost impossible to perform without you. Kudos!