Google Scholar: the ultimate guide
What is Google Scholar?
Google Scholar (GS) is a free academic search engine that can be thought of as the academic version of Google. Rather than searching all of the indexed information on the web, it searches repositories of publishers, universities or scholarly websites.
This is generally a smaller subset of the pool that Google searches. It's all done automatically, but still most of the results of a search tend to be reliable scholarly sources. However, Google is also less careful in what it includes in search results than are more curated subscription based, academic databases such as Scopus and Web of Science, so it is worth making your own assessment of the credibility of the resources linked through Google Scholar.
Why is it better than "normal" Google for finding research papers?
We all use Google for our daily internet searches, so why should we switch to Google Scholar?
One advantage of using Google Scholar is that the interface is comforting and familiar to anyone who uses Google. This lowers the learning curve of finding scholarly information. There are a number of useful differences from a regular Google search, such as
- the option to copy a formatted citation in different styles including MLA and APA
- export bibliographic data (BibTeX, RIS) to use with reference management software
- links that let you explore which other works have cited the listed work
- links that let you easily find full text versions of the article
Although it is free to search in Google Scholar, most of the content is not freely available, but Google does its best to find copies of restricted articles in public repositories which often contain earlier drafts (preprints). If you are at an academic or research institution, you can also set up a library connection to highlight items which are available through your institution’s subscriptions.
The Google Scholar search results page
Since searching in Google Scholar is as straightforward as searching in Google, it's best to jump right in and give it a try.
The search result page is, however, different and it is worth being familiar with the different pieces of information that are shown. Let's have a look at the results for the search term "machine learning”.
The first two lines: core bibliographic information
The first two lines of each result provide the title of the document (e.g. of an article, book, chapter, or report). The second line provides the bibliographic information about the document, in order: the author(s), the journal or book it appears in, the year of publication, and the publisher. Clicking on the title link will bring you to the publisher’s page where you may be able to access more information about the document including the abstract, and options to download the PDF of the document.
Quick full text-access options
To the far right of the entry are more direct options for obtaining the full text of the document. In this example, Google has also located a publicly available PDF of the document hosted at umich.edu. Note, that it's not guaranteed that it is the version of the article that was finally published in the journal.
The bottom line: "Cited by" count and other useful links
Below the text snippet/abstract you can find a number of useful links. The first of these is the Cited by link will show other articles that have cited this resource. That is a super useful feature that can help you in many ways. First, it is a good way to track the more recent research that has referenced this article, and second the fact that other researches cited this document lends greater credibility to it. But be aware that there is a lag in publication type. Therefore, an article published in 2017 will not have an extensive number of cited by results. It takes a minimum of 6 months for most articles to get published, so even if an article was using the source, the more recent article has not been published yet.
The Versions link will display other versions of the article or other databases where the article may be found, some of which may offer free access to the article.
Clicking on the quotation mark icon will display a popup with commonly used citation formats such as MLA, APA, Chicago, Harvard, and Vancouver that may be copy and pasted. Note, however, that the Google Scholar citation data is sometimes incomplete and so it is often a good idea to check this data at the source - i.e. by following the title link to the publishers' website. The "cite" popup also includes links for exporting the citation data as BibTeX or RIS) files that any major reference manager can import.
Pro tips for your literature search
Although Google Scholar limits each search to a maximum of 1,000 results, it's still too much to explore, and you need an effective way of locating the relevant articles. We have put together a list of pro tips that will help you save time and search more effectively:
- Google Scholar searches are not case sensitive. That means a search for "Machine Learning" will produce the same results as a search for "machine learning".
- Use keywords instead of full sentences. Let's say your research topic is about self driving cars. For a regular Google search we might enter something like "what is the current state of the technology used for self driving cars". In Google Scholar you will see less than ideal results for this query. The trick is to build a list of keywords and perform searches for them like self-driving cars, autonomous vehicles, or driverless cars. Google Scholar will assist you on that: if you start typing in the search field you will see related queries suggested by Scholar!
- Use quotes to search for an exact match. If you put your search phrase into quotes you can search for exact matches of that phrase in the title and the body text of the document. Without quotes, Google Scholar will treat each word separately. This means that if you search national parks, the words will not necessarily appear together. Grouped words and exact phrases should be enclosed in quotation marks.
- Add the year to the search phrase to get articles published in a particular year. A search using e.g. self-driving cars 2015, will return articles or books published in 2015.
- Use the side bar controls to adjust your search result. Using the options in the left hand panel you can further restrict the search results by limiting the years covered by the search, the inclusion or exclude of patents, and you can sort the results by relevance or by date.
- Use Boolean operator to better control your searches. Searches are not case sensitive, however, there are a number of Boolean operators you can use to control the search and these must be capitalized.
- AND requires both of the words or phrases on either side to be somewhere in the record.
- NOT can be placed in front of a word or phrases to exclude results which include them.
- OR will give equal weight to results which match just one of the words or phrases on either side.
In case you got overwhelmed by those many options, we have put together some illustrative examples below:
|Example queries||When to use and what will it do?|
|"alternative medicine"||Multiword concepts like alternative medicine are best searched as an exact phrase match. Otherwise Google Scholar will display results that contain alternative and/or medicine.|
|"The wisdom of the hive: the social physiology of honey bee colonies"||If you are looking for a particular article and you know the title it is best to put it into quotes to look for an exact match.|
|author:"Jane Goodall"||A query for a particular author, e.g. Jane Goodall. Also "J Goodall" or "Goodall" will work, but will be less restrictive.|
|"self-driving cars" AND "autonomous vehicles"||Only results will be show that contain both the phrases "self-driving cars" and "autonomous vehicles"|
|dinosaur 2014||Limits search results about dinosaurs to aticles that were publsihed in 2014|
The advanced search interface
You can gain even more fine-grained control over your search by using the advanced search feature.
If you are in the exploration stage of information seeking, then advanced search could prematurely limit the information you are seeing, but if you are familiar with the results that are returned, then advanced search tools can give you additional controls over the search to help you narrow in on more relevant results. This feature is available by clicking on the hamburger menu in the upper left and selecting the "Advanced search" menu item.
The fields are fairly self-explanatory. This advanced search depicted above, for example, would results in articles or book titles published between 1990 and 2000 which include the words dinosaur, fossils and devonian but do not include the phrase “United States” anywhere in the title or text (if available) of the search result.
Customizing search preferences and options
Adjusting the Google Scholar settings is not necessary for getting good results but offers some additional customization, including the ability to enable the above-mentioned library integrations. The settings menu is found in the hamburger menu located in the top left of the Google Scholar page. The settings are divided into five sections:
- Search Results - this section has the most common controls, including:
- Collections to search - by default Google scholar searches articles and includes patents, but this default can be changed here if you are not interested in patents or if you wish to often search case law instead.
- Bibliographic manager - if you are using an academic reference manager other than Paperpile, you can enable the export of the relevant citation data format via the “Bibliography manager” subsection. The available options are BibTex (for Latex editors), EndNote (for EndNote), RefMan (for RefMan, Zotero, and Mendeley, among other), and RefWorks.
- Languages - If you wish for results to return only articles written in a specific subset of languages, you can define that here.
- Library links - As noted, Google Scholar allows you to get the Full Text of articles through your institution’s subscriptions - where available. Search for and add your institution(s) here to have the relevant link included in your search results.
- Button - The Scholar Button is a Chrome extension which add a dropdown search box to your toolbar - allowing you to search Google Scholar from any website. Moreover, if you have any text selected on the page and then click the button it will display results from a search on those words when clicked.
Use the "My library" feature to bookmark articles you want to read later on
When signed in, Google Scholar adds some simple tools for keeping track of and organizing the articles you find. These can be useful if you are not using a full academic reference manager.
All the search results include a “save” button at the end of the bottom row of links, clicking this will add it to your "My Library".
To help you provide some structure, you can create and apply labels to the items in your library. Appended labels will appear at the end of the article titles. For example, the following article has been assigned a “RNA” label:
Within your Google Scholar library, you can also edit the metadata associated with titles. This will often be necessary as Google Scholar citation data is often faulty.
The scope and limitations of Google Scholar
There is no official statement about how big the Scholar search index is, but unofficial estimates are in the range of about 160 millions, and it is supposed to continue to grow by several millions each year. Yet, Google Scholar does not return all resources that you may get in search at you local library catalog. For example, a library database could return podcasts, videos, articles, statistics, or special collections. For now, Google Scholar has only the following publication types:
- Journal articles: articles published in journals. It's a mixture of articles from peer reviewed journals, predatory journals and pre-print archives.
- Books: Links to the Google limited version of the text, when possible.
- Book chapters: Chapters within a book, sometimes they are also electronically available.
- Book reviews: Reviews of books, but it is not always apparent that it is a review from the search result.
- Conference proceedings:- Papers written as part of a conference, typically used as part of presentation at the conference.
- Court opinions
- Patents: Google Scholar only searches patents if the option is selected in the search settings described above.
The information in Google Scholar is not cataloged by professionals. The quality of metadata will depend heavily on the source that Google Scholar is pulling the information from. This is a much different process to how information is collected and indexed in scholarly databases such as Scopus or Web of Science.
A brief history of Google Scholar
The key inventor behind Google Scholar is Anurag Acharya, who has been on the Google Scholar Team since it was released back in 2004. Check out this piece in WIRED for the whole background story. Here is a brief timeline of the updates that happened since then:
- June 1010: Google Scholar Alerts was launched
- November 2011: Google Scholar Citations was launched
- April 2012: Google Scholar [Metrics are released for the first time
- May 2012: complete overhaul of the Google Scholar interface
- October 2012: the cite feature was introduced and allows to fetch a MLA, APA or Chicago citation of an article
- November 2013: Google Scholar Library is released which allows users to save articles found in Google Scholar to a personal library
- June 2016: query suggestions like we know them from regular Google searches are now also available in Google Scholar
- August 2016: ability to add labels to articles stored in a user's personal Google Scholar library
- September 2017: redesign of the Google Scholar results page
- March 2018: improved experience for mobile phones
- August 2018: 2018 Scholar Metrics released
If you want to dig deeper then take a look at the official Google Scholar Blog.
Alternatives to Google Scholar
Google Scholar is by far the most frequently used academic search engine, but it is not the only one. There is Microsoft Academic which after its relaunch in 2015 seems to be the closest competitor. The newt kid on the block is Semantic Scholar developed by the non-profit Allen Institute for Artificial Intelligence. It's currently corpus consists of about 40 million citations in computer.
Country specific Google Scholar editions
- scholar.google.fr: Sur les épaules d'un géant
- scholar.google.es (Google Académico): A hombros de gigantes
- scholar.google.pt (Google Académico): Sobre os ombros de gigantes
- scholar.google.de: Auf den Schultern von Riesen