Google gives us a detailed explanation of what causes algorithm to rewrite meta descriptions.

In a Webmaster Central hangout, a publisher asked Google’s John Mueller why their meta description was being rewritten.
Mueller’s answer offered a peek into how Google’s algorithm chooses when to rewrite meta descriptions.

The question was specifically about a meta description on the home page being rewritten on the Google search results pages
(SERPs) for branded search queries. The publisher used the example of using the modifier “UK” with the brand name.

There are no specifics mentioned in the question so there is no way to address the publisher’s issue directly.

But because Mueller’s answer is general, it provided an answer that gave some insight into why Google rewrites meta descriptions.

Here’s the question

“We have an issue with the meta description that is being displayed for hour home page.

So, even though we have a meta description that is being implemented on that particular page, somehow in Google when our website appears, the meta description is completely different.

And in some cases, if we search for our company name plus the word “UK,” the meta description makes no sense whatsoever.
It’s just a bunch of words put together from various parts of the page.

I know sometimes Google goes hunting for various things on the page if it cannot find relevant content for that particular region.

So I guess my question is, because we have a lot of traffic that is coming up from branded searches… it is important for us to have the correct meta description showing up.”

What do we do to rectify the situation?”

John Mueller Explains What Causes Meta Description Rewrites

Before answering why Google rewrites meta descriptions, John Mueller stated he hasn’t seen the publishers specific search
result and could not answer why it was specifically happening for a query he hasn’t seen.

“It’s hard to say without looking at the search results. So that’s kind of the one part.”

Then he offered explanations of what causes Google to rewrite meta descriptions.

First he states that you have to have a meta keyword:

“Usually what happens is we need to have the description meta tag on the page. That’s kind of the first step.

It sounds like you already have that set up.”

Reason 1: Poor Use of Meta Description

Now the explanation of what triggers Google’s algorithm to rewrite the meta description tag:

“The other thing there is that we need to be able to, I guess, trust the meta description on the page so that it looks kind of reasonable.

In particular, sometimes when we see a bunch of keywords that are just kind of collected in the meta description.

Then that’s something that our systems might look at and say well, this doesn’t look that useful for users.

So they’ll try to rewrite something else.”

Mueller is stating that one reason why the meta portrayal might be changed is on the grounds that it’s centered more
around catchphrases and less on what the page is about.

In any case, more significantly, what makes that meta description an objective for changing is that he said that it “doesn’t look that helpful for clients.”

Reason 2: Content and Query Matching Can Trigger Meta Description Rewrite

That “less useful” part, in the context of the above publisher, is relative to the search query.
The publisher said that branded queries with the “UK modifier were being rewritten.

That “UK” search query modifier may be what’s causing Google to rewrite the meta description.

If the web page itself isn’t specifically sending UK related content signals then Google might choose to modify the meta description.

Adding modifiers to search queries can cause Google to rewrite the meta descriptions (and title tags too).
This is especially going to happen when the keyword modifiers (like UK or Home Page) don’t exist in the written content of the page.

Reason 3: Search Query Influences Meta Description Rewrite

As I illustrated above, and John Mueller will say below, the meta description rewriting depends on the search query.
And I would expand that to say that it depends on the search query and the content on the web page.

Here’s what Mueller said:

“And the other thing… you noticed, is the description can vary depending on the query that is used.

So the first thing that I would do is just take the normal branded query that you use and double check that the description that you provide in the meta description is actually pretty useful and not too… spammy or overdone.

And then go from there, essentially, to figure out… is this something where Google always gets it wrong?

Or is it something where sometimes Google’s algorithms pick up something else on the page and get it wrong?”

Google Meta Description Rewriting Explained

John Mueller gave a great explanation of the reason why Google rewrites search queries.

I know some people are going to react and say that Google’s rewriting is arbitrary. But it’s not arbitrary.

This article has described specific situations that cause Google’s algorithm to rewrite meta description tags.

Google’s algorithm rewrites meta descriptions based on the relationship between the search query and the web page content.

So if you have an issue with Google rewriting the meta tags, take a closer look at how the search query relates to the on-page content.
And contact us

Source: Roger Montti https://www.searchenginejournal.com/why-google-rewrites-meta-descriptions/370452/?utm_source=email&utm_medium=daily-newsletter&utm_campaign=daily-newsletter

Other References: SEO Best Practices: How to Create Awesome Meta Descriptions
6 Mistakes to Avoid When Writing Your Meta Descriptions
Google on How it Handles Extra Meta Descriptions and Title Tags