Google Trends provides access to a largely unfiltered sample of actual search requests made to Google. It’s anonymized (no one is personally identified), categorized (determining the topic for a search query) and aggregated (grouped together). This allows us to display interest in a particular topic from around the globe or down to city-level geography.
What samples are provided?
There are two samples of Google Trends data that can be accessed:
Real-time data is a sample covering the last seven days.
Non-realtime data is a separate sample from real-time data and goes as far back as 2004 and up to 72 hours before your search.
How is a sample of searches representative?
While only a sample of Google searches are used in Google Trends, this is sufficient because we handle billions of searches per day. Providing access to the entire data set would be too large to process quickly. By sampling data, we can look at a dataset representative of all Google searches, while finding insights that can be processed within minutes of an event happening in the real world.
How is Google Trends data normalized?
Google Trends normalizes search data to make comparisons between terms easier. Search results are normalized to the time and location of a query by the following process:
Each data point is divided by the total searches of the geography and time range it represents to compare relative popularity. Otherwise, places with the most search volume would always be ranked highest.
The resulting numbers are then scaled on a range of 0 to 100 based on a topic’s proportion to all searches on all topics.
Different regions that show the same search interest for a term don't always have the same total search volumes.
What searches are included in Google Trends?
Google Trends data reflects searches people make on Google every day, but it can also reflect irregular search activity, such as automated searches or queries that may be associated with attempts to spam our search results.
While we have mechanisms in place to detect and filter irregular activity, these searches may be retained in Google Trends as a security measure: filtering them from Google Trends would help those issuing such queries to understand we’ve identified them. This would then make it harder to keep such activity filtered out from other Google Search products where high-fidelity search data is critical. Given this, those relying on Google Trends data should understand that it’s not a perfect mirror of search activity.
Google Trends does filter out some types of searches, such as:
Searches made by very few people: Trends only shows data for popular terms, so search terms with low volume appear as "0"
Duplicate searches: Trends eliminates repeated searches from the same person over a short period of time.
Special characters: Trends filters out queries with apostrophes and other special characters.
Is Google Trends the same as polling data?
Google Trends is not a scientific poll and shouldn’t be confused with polling data. It merely reflects the search interest in particular topics. A spike in a particular topic does not reflect that a topic is somehow “popular” or “winning,” only that for some unspecified reason, there appear to be many users performing a search about a topic. Google Trends data should always be considered as one data point among others before drawing conclusions.
How can I better make use of and interpret Google Trends data?
This post from Google News Lab explains more about how Google Trends works and ways people might appropriately make use of the data.
How does trends data shared by Google News Lab differ from Google Trends?
For major events, the Google News Lab may share trends data (such as via Twitter) that is not accessible via the public Google Trends tool. We do monitor such data for evidence of irregular activity. However, as with regular Google Trends data, it is not scientific and might not be a perfect mirror of search activity.
How does Google Trends differ from Autocomplete?
Autocomplete is a feature within Google Search designed to make it faster to complete searches that you’re beginning to type. The predictions come from real searches that happen on Google and show common and trending ones relevant to the characters that are entered and also related to your location and previous searches.
Unlike Google Trends, Autocomplete is subject to Google’s removal policies as well as algorithmic filtering designed to try to catch policy-violating predictions and not show them. Because of this, Autocomplete should not be taken as always reflecting the most popular search terms related to a topic.
How does Google Trends differ from AdWords search data?
The AdWords search terms report is meant for insights into monthly and average search volumes, specifically for advertisers, while Google Trends is designed to dig further into more granular data in real time.