How Google Search Works (in 5 minutes) — transkrip

Every day, billions of people come here with questions

about all kinds of things.

Sometimes we even get questions about Google Search itself,

like how this whole thing actually works.

And while this is a subject entire books have been written

about, there is a good chance you're

in the market for something a little more concise.

So let's say it's getting close to dinner

and you want a recipe for lasagna.

You've probably seen this before.

But let's go a little deeper.

Since the beginning, back when the home page looked like this,

Google has been continuously mapping

the web, hundreds of billions of pages,

to create something called an index.

Think of it as the giant library we

look through whenever you do a search for lasagna or anything

else.

Now, the word lasagna shows up a lot on the web--

pages about the history of lasagna,

articles by scientists whose last name

happened to be Lasagna, stuff other people

might be looking for.

But if you're hungry, randomly clicking through millions

of links is no fun.

This is where Google's ranking algorithms come into play.

First, they try to understand what

you're looking for so they can be helpful even if you don't

know exactly the right words to use

or if your spelling is a little off.

Then they sift through millions of possible matches

in the index and automatically assemble

a page that tries to put the most relevant information

up top for you to choose from.

OK.

Now we have some results.

But how did the algorithms actually decide

what made it onto the first page?

There are hundreds of factors that

go into ranking search results.

So let's talk about a few of them.

You may already know that pages containing

the words you search for are more

likely to end up at the top.

No surprise there.

But the location of those words, like in the page's title,

or in an image's caption, those are factors, too.

There's a lot more to ranking than just words.

Back when Google got started, we looked

at how pages linked to each other

to better understand what pages were about

and how important and trustworthy they seemed.

Today, linking is still an important factor.

Another factor is location, where a search happens.

Because, if you happen to be in Ormea, Italy,

you might be looking for information

about their annual lasagna festival.

But if you're in Omaha, Nebraska, you probably aren't.

When a web page was uploaded is an important factor, too.

Pages published more recently often

have more accurate information, especially

in the case of a rapidly developing news story.

Of course, not every site on the web is trying to be helpful.

Just like with robocalls on your phone or spam in your email,

there are a lot of sites that only exist to scam.

And every day, scammers upload millions more of them.

So just because InstantVirusDownload.net

lists the words "lasagna recipe" 400 times,

that doesn't mean it's going to help you make dinner.

We spend a lot of time trying to stay one step ahead of tricks

like these, making sure our algorithms can recognize scam

sites and flag them before they make it to your search results

page.

So let's review.

Billions of times a day, whenever

someone searches for lasagna, or resume writing tips,

or how to swaddle a baby, or anything else,

Google software locates all the potentially relevant results

on the web, removes all the spam,

and ranks them based on hundreds of factors, like keywords,

links, location, and freshness.

OK.

Good time to take a breath.

This last part is about how we make changes to Search.

And it's important.

Since 1998, when Google went online,

people seem to have found our results pretty helpful.

But the web is always changing and people are always

searching for new things.

In fact, one in every seven searches

is for something that's never been typed into the search

box before by anyone ever.

So we're always working on updates to Search,

thousands every year.

Which brings up a big question.

How do we decide whether a change

is making Search more helpful?

Well, one of the ways we evaluate

potential updates to Search is by asking people like you.

Every day, thousands of Search quality raters

look at samples of Search results side by side,

then give feedback about the relevance and reliability

of the information.

To make sure those evaluations are consistent,

the raters follow a list of Search quality evaluator

guidelines.

Think of them as our publicly available guide to what

makes a good result good.

Oh, and one last thing to remember.

We use responses from raters to evaluate changes.

But they don't directly impact how Search results are ranked.

So there you have it.

Every time you click Search, our algorithms

are analyzing the meaning of the words in your search,

matching them to the content on the web,

understanding what content is most

likely to be helpful and reliable,

and then automatically putting it all together

in a neatly organized page designed to get you the info

you need.

All in, oh, 0.81 seconds?

Wow.

Anyone else ready for dinner?

Interested in learning more?

We've got a whole website dedicated to how Search works.

Just click right here.

Want to read the Search Quality Rater Guidelines for yourself?

Click right here.