SPEAKER: 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.
