Search Central LiveDeep Dive Europe 2026

Knowledge base v2.13.0 · Community edition · data through 2 October 2026

Topic · The index and its signals

Signals calculated during indexing

Of the many signals Google calculates during indexing, it singled out country, language, freshness, SafeSearch and spam as having large effects, and said country and language have been among its most important signals since its early days. Google stores one language per page and weights language and country in index selection so the index is not dominated by English or by the largest countries (said at the event, not in Google's docs). Some freshness signals are calculated at indexing but used in ranking for queries that deserve fresh results, and Google said freshness plays no big role in whether a page is indexed (not in its docs). SafeSearch signals are calculated at indexing because ranking runs online with no time for them, need the whole parsed page plus its inbound and outbound links, and, Google said, do not change a page's chance of being indexed (the timing and indexing points are not in its docs); Google's guidelines advise keeping explicit content on a separate domain or subdomain so the whole site is not filtered. Each indexed document carries its calculated signals for index selection to use; Google said many are documented under other names, but that creating content users like is a better use of time than hunting for signals. Day 3 showed where these signals are used next: at retrieval Google orders candidates with per-document signals collected during indexing, language first and then country. Google added that its slowest signal is recalculated only about once a year, which is why a site move can take up to a year (a partly uncertain passage of the recording). Day 1's second recording added that the signals calculated during indexing are stored and used both for index selection and later for ranking.

Based on D2-C648, D2-C649, D2-C586, D2-C651, D2-C652, D2-C653, D2-C657, D2-C656, D2-C658, D2-C662, D2-C663, D2-C661, D2-C664, D2-C722, D2-C687, D2-C678, D2-C679, D2-C677, D2-C665, D2-C659, D2-C590, D3-C076, D3-C079, D3-C644, D1-C205

25 claims · raised in 7 sessions · said or shown on Day 1 and Day 2 and Day 3

Open in Reef mapOpen in Graph

Things in this topic 2

Counts are claims that name the thing. All things

What to do

  • After fixing a page's language, country targeting or content that triggers SafeSearch, request recrawling of key URLs; signals calculated at indexing change only when the page is reprocessed.
  • Keep explicit content on its own domain or subdomain.
  • Do not change dates or make cosmetic edits to get old pages indexed; freshness helps only for queries that deserve fresh results.
  • Keep each page in one language, translating templates along with the main text, because Google records a single language per page.

Day 1: Crawling 1

Said on stage 1

StageConsistent with docsD1-C205

Signals calculated for a page during indexing are stored in the index and used both to decide whether the page gets indexed and, later, for ranking.

Speaker Cherry PrommawinIn Day 1, 11:45 · How Search works and where's AI?Evidence transcript

  • Extends D1-C037 Day 1: For classic Search, crawling means Googlebot, scheduling and robots.txt, with AI used in parts such as…
  • Extended by D2-C687 Day 2: Index selection uses the signals calculated earlier in indexing for each document it has to select or discard.

Day 2: Indexing 21

Said on stage 16

StageConsistent with docsD2-C648

Among the many signals Google calculates during indexing, the ones singled out as having large effects on search results were country, language, freshness, SafeSearch and spam.

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

  • Extends D1-C037 Day 1: For classic Search, crawling means Googlebot, scheduling and robots.txt, with AI used in parts such as…
StageConsistent with docsD2-C649

Country and language are among Google's most important signals and have been used since Google's early days.

“Both of them are extremely, extremely important”

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

  • Extended by D3-C079 Day 3: To order candidates at retrieval, Google uses signals collected during indexing, and the first two are…
  • Extended by D3-C082 Day 3: Country is the second retrieval signal: a user searching from Switzerland wants cheese from Switzerland, not…
StageNot in docsD2-C651

Google detects the language of each document and weights language in index selection so that the index is not dominated by one or two languages.

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

Things
  • Extends D2-C585 Day 2: Google determines a page's language for indexing from the page content, not from a language code in the URL.
StageConfirmed by docsD2-C654

In ranking, country and language signals help Google serve users the right content for their country and language.

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

  • Extended by D3-C006 Day 3: Google's first step in understanding almost any query is to detect its language, which tells Google roughly…
  • Extended by D3-C080 Day 3: At retrieval, Google tries to match results to the user's language wherever possible: someone searching in…
StageConfirmed by docsD2-C656

Freshness is a signal for queries that deserve fresh results ('query deserves freshness'): when a breaking event hits a city, such as possible closure of Barcelona's airport, users want really fresh results, not results from two weeks ago.

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

  • Extends D1-C045 Day 1: Ranking signals differ by result type: web pages (text, links, passages), images (resolution, colour…
  • Extended by D3-C487 Day 3: Google's ranking systems guide describes 'query deserves freshness' systems that show fresher content where…
StageConfirmed by docsD2-C660

Google uses multiple systems to protect users from unexpected explicit results: its algorithms detect whether a user is looking for explicit content and rank results accordingly, so the aim is not to never show explicit results but to avoid showing them to users who are not looking for them.

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

StageNot in docsD2-C662

Google calculates SafeSearch signals during indexing rather than in ranking, because ranking happens online with no time for such calculations, while indexing has the processing power.

“In ranking, everything has to happen online, and there's just not enough time to calculate those things.”

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

StageD2-C679

Combing Google's documentation for signals is not the best use of an SEO's time; creating content that users will like is a better one.

“If you are just focusing on actually creating the content that users will like, then that's probably a better use of your life.”

Speaker GoogleIn Day 2, 15:30 · Calculating (some) signalsEvidence transcript

  • Repeats D1-C059 Day 1: The opening keynote closed with the advice to think about UEO, user engine optimisation, next to SEO and GEO…
StageConsistent with docsD2-C722

Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

Speaker GoogleIn Day 2, 16:15 · How does the index look like?Evidence transcript

  • Extends D1-C037 Day 1: For classic Search, crawling means Googlebot, scheduling and robots.txt, with AI used in parts such as…
  • Repeated by D3-C076 Day 3: For retrieval, Google uses signals attached individually to each document in the index.
  • Extended by D3-C079 Day 3: To order candidates at retrieval, Google uses signals collected during indexing, and the first two are…
  • Extended by D3-C083 Day 3: Google called quality the most important of the signals used to order candidates at retrieval: a URL of high…

What Google's documentation says 2

Analysis by the author 3

AnalysisD2-C665

Because explicit content on its own does not lower a page's chance of being indexed, the practical risk for a site that mixes explicit and general content is SafeSearch classification, which looks at the whole page and its links; keep explicit pages on a separate domain or subdomain, as Google advises.

Author Ibrahim AnjroAnnotates Day 2, 15:30 · Calculating (some) signals

Used byrequirement DEV-IDX-12

AnalysisD2-C677

Language, country, SafeSearch and spam signals, and some freshness signals, are calculated when a page is indexed, so a fix such as correcting a page's language or removing content that triggers SafeSearch only counts once Google recrawls and reprocesses the page; request recrawling of the most important URLs after the fix.

Author Ibrahim AnjroAnnotates Day 2, 15:30 · Calculating (some) signals

Used byrequirements DEV-IDX-12, DEV-MON-02

Day 3: Serving: Ranking, Search Console, and Performance 3

Said on stage 3

StageConsistent with docsD3-C079

To order candidates at retrieval, Google uses signals collected during indexing, and the first two are language and country.

Speaker Gary IllyesIn Day 3, 10:25 · Making sense of users' queriesEvidence transcript

Used byrequirement DEV-INT-07glossary term Retrieval

  • Extends D2-C722 Day 2: Each document in Google's index has pretty much all the signals calculated for it attached, for example…
  • Extends D2-C649 Day 2: Country and language are among Google's most important signals and have been used since Google's early days.

Across days and sessions 15

  1. Stage D1-C205 Day 1 · How Search works and where's AI?

    Signals calculated for a page during indexing are stored in the index and used both to decide whether the page gets indexed and, later, for ranking.

    extends
    Slide D1-C037 Day 1 · How Search works and where's AI?

    For classic Search, crawling means Googlebot, scheduling and robots.txt, with AI used in parts such as scheduling. Indexing is one big but not limitless index that calculates signals and understands more than words, with AI such as BERT. Serving uses hundreds of signals tailored to the moment, with AI such as RankBrain.

  2. Stage D2-C648 Day 2 · Calculating (some) signals

    Among the many signals Google calculates during indexing, the ones singled out as having large effects on search results were country, language, freshness, SafeSearch and spam.

    extends
    Slide D1-C037 Day 1 · How Search works and where's AI?

    For classic Search, crawling means Googlebot, scheduling and robots.txt, with AI used in parts such as scheduling. Indexing is one big but not limitless index that calculates signals and understands more than words, with AI such as BERT. Serving uses hundreds of signals tailored to the moment, with AI such as RankBrain.

  3. Stage D2-C651 Day 2 · Calculating (some) signals

    Google detects the language of each document and weights language in index selection so that the index is not dominated by one or two languages.

    extends
    Stage D2-C585 Day 2 · Focusing on Internationalisation and Localisation

    Google determines a page's language for indexing from the page content, not from a language code in the URL.

  4. Stage D2-C656 Day 2 · Calculating (some) signals

    Freshness is a signal for queries that deserve fresh results ('query deserves freshness'): when a breaking event hits a city, such as possible closure of Barcelona's airport, users want really fresh results, not results from two weeks ago.

    extends
    Slide D1-C045 Day 1 · How Search works and where's AI?

    Ranking signals differ by result type: web pages (text, links, passages), images (resolution, colour, associated text), news (freshness, originality, diversity), local (location, type, rating, reviews, hours) and videos (language, text from speech).

  5. Stage D2-C687 Day 2 · Deciding what goes in the index?

    Index selection uses the signals calculated earlier in indexing for each document it has to select or discard.

    extends
    Stage D1-C205 Day 1 · How Search works and where's AI?

    Signals calculated for a page during indexing are stored in the index and used both to decide whether the page gets indexed and, later, for ranking.

  6. Stage D2-C722 Day 2 · How does the index look like?

    Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

    extends
    Slide D1-C037 Day 1 · How Search works and where's AI?

    For classic Search, crawling means Googlebot, scheduling and robots.txt, with AI used in parts such as scheduling. Indexing is one big but not limitless index that calculates signals and understands more than words, with AI such as BERT. Serving uses hundreds of signals tailored to the moment, with AI such as RankBrain.

  7. Stage D3-C006 Day 3 · Making sense of users' queries

    Google's first step in understanding almost any query is to detect its language, which tells Google roughly what content the user wants: a query in German suggests German content, a query in English English content.

    extends
    Stage D2-C654 Day 2 · Calculating (some) signals

    In ranking, country and language signals help Google serve users the right content for their country and language.

  8. Stage D3-C079 Day 3 · Making sense of users' queries

    To order candidates at retrieval, Google uses signals collected during indexing, and the first two are language and country.

    extends
    Stage D2-C649 Day 2 · Calculating (some) signals

    Country and language are among Google's most important signals and have been used since Google's early days.

  9. Stage D3-C079 Day 3 · Making sense of users' queries

    To order candidates at retrieval, Google uses signals collected during indexing, and the first two are language and country.

    extends
    Stage D2-C722 Day 2 · How does the index look like?

    Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

  10. Stage D3-C080 Day 3 · Making sense of users' queries

    At retrieval, Google tries to match results to the user's language wherever possible: someone searching in Spanish does not necessarily want results in Italian.

    extends
    Stage D2-C654 Day 2 · Calculating (some) signals

    In ranking, country and language signals help Google serve users the right content for their country and language.

  11. Stage D3-C082 Day 3 · Making sense of users' queries

    Country is the second retrieval signal: a user searching from Switzerland wants cheese from Switzerland, not from Germany, and a user in Spain is poorly served by results targeting a South American country.

    extends
    Stage D2-C649 Day 2 · Calculating (some) signals

    Country and language are among Google's most important signals and have been used since Google's early days.

  12. Stage D3-C083 Day 3 · Making sense of users' queries

    Google called quality the most important of the signals used to order candidates at retrieval: a URL of high quality is more likely to be retrieved from the index for specific queries.

    extends
    Stage D2-C722 Day 2 · How does the index look like?

    Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

  13. Analysis D3-C487 Day 3 · Lightning session L: Understanding SERPs and your users

    Google's ranking systems guide describes 'query deserves freshness' systems that show fresher content where it would be expected, which is narrower than a general preference for fresh content; refresh pages whose queries expect current information, and judge other refreshes by quality.

    extends
    Stage D2-C656 Day 2 · Calculating (some) signals

    Freshness is a signal for queries that deserve fresh results ('query deserves freshness'): when a breaking event hits a city, such as possible closure of Barcelona's airport, users want really fresh results, not results from two weeks ago.

  14. Stage D2-C679 Day 2 · Calculating (some) signals

    Combing Google's documentation for signals is not the best use of an SEO's time; creating content that users will like is a better one.

    repeats
    Stage D1-C059 Day 1 · Welcome and opening keynotes

    The opening keynote closed with the advice to think about UEO, user engine optimisation, next to SEO and GEO: focus on the user and the rest will follow.

  15. Stage D3-C076 Day 3 · Making sense of users' queries

    For retrieval, Google uses signals attached individually to each document in the index.

    repeats
    Stage D2-C722 Day 2 · How does the index look like?

    Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

Built on these claims 4

Developer requirements 4

Sources 5