Caselaw Access Project Citation Graph

The Caselaw Access Project is now sharing a citation graph of the 6.7 million cases in our collection from Harvard Law School Library. This update makes available a CSV file that lists case IDs and the cases they cite to. Here’s where you can find it:

This citation graph shows us how cases are connected; it lets us find relationships between cases, like identifying the most influential cases and jurisdictions. This update is a new resource for finding those patterns. In the future, we want to use the CAP citation graph to create visualizations to show these relationships. We’re excited for you to do the same.

Have something to share? Send it our way! We’re looking forward to hearing from you.

Caselaw Access Project Shares PDFs for All Cases

The Caselaw Access Project is now making scanned PDFs available for every case in our collection.

This update makes all cases in the CAP case browser available as PDF, digitized from the collections of Harvard Law School Library. When viewing a case, just select the “view PDF” option above the title.

We’re also making volume-level PDFs available as part of CAP downloads. This will let users access PDF files for entire volumes, organized by jurisdiction and reporter.

Case and volume PDFs are available without restriction for our open jurisdictions (Illinois, Arkansas, New Mexico, and North Carolina). PDF files from closed jurisdictions are restricted to 500 cases per-person, per-day, with volume-level PDF access limited to authorized researchers.

This update creates new ways to read cases, online, for free. Are you using the Caselaw Access Project to read case law? We’re looking forward to hearing about it.

Caselaw Access Project Links Case Citations

The Caselaw Access Project is taking its first steps to create links to case citations in our collection of 6.7 million cases.

This update makes case citations available as links in the CAP case browser. When viewing a case, citations are shown as links.

United States v. Kennedy, 573 F.2d 657 (1978) displaying in-text link to "407 F.2d 1391".

When you click on a citation, you’ll go directly to that case.

We also created a cites_to field in the Caselaw Access Project API. This new field shows which cases an opinion cites to. Here’s what that looks like.

United States v. Kennedy, 573 F.2d 657 (1978) showing "cites_to" field in Caselaw Access Project API.

This is only the beginning of our work with case citations. In the future, we hope to improve citation extraction and ultimately to offer researchers a citation graph.

Are you using the Caselaw Access Project to understand the relationship between cases with case citations? Tell us about it.

CAP Code Share: Caselaw Access Project API to CSV

Today we’re going to learn how to write case data from the Caselaw Access Project API to CSV. This post shows work from Jack Cushman, Senior Developer at the Harvard Library Innovation Lab.

The Caselaw Access Project makes 6.7 million individual cases freely available from Harvard Law School Library. With this code, we can create a script to get case data from the Caselaw Access Project API, and write that data to a spreadsheet with Python. This demo is made available as part of the CAP Examples repository on Github. Let’s get started!

How does this script find the data it’s looking for? This happens with an API call using the CAP API, and retrieves all cases that include the words “first amendment”: Want to create your own CAP API call? Here’s how.

The Caselaw Access Project has structured, case-level metadata. You can query parts of that data using the CAP API with endpoints, like “court” or “jurisdiction”. Here’s a rundown of the endpoints we have. This demo gets data using these endpoints to write case data to a CSV file: 'id', 'frontend_url', 'name', 'name_abbreviation', 'citation', 'decision_date', 'jurisdiction'. You can adapt this code, and choose your own endpoints.

To run this script, find your CAP API key by creating an account or logging in, and viewing your user details.

This code is part of the CAP Examples repository on Github, a place to find and share code for working with data from the Caselaw Access Project. Do you have code to share? We want to see this resource grow.

Are you creating new things with code or data made available by the Caselaw Access Project? Send it our way. Our inbox is always open.

Caselaw Access Project Downloads Now Available

Today we're announcing CAP downloads, a new way to access select datasets relating to the Caselaw Access Project. While researchers can use our API and bulk data to access standardized metadata and text for all of the cases in the CAP dataset, we also want to make it possible to share specialized and derivative datasets.

How does it work?

Everything available for download is presented in a simple file directory that lets you navigate to the specific dataset or file you want. Each dataset or export comes with a README file that includes basic information about it.

What data do we have?

To view and access what's currently available, visit We're starting with:

What other datasets should we share?

If you have ideas or suggestions for other datasets you'd like us to share, we'd love to hear about it. Contact us at!

Caselaw Access Project Shares Scanned Images for Open Jurisdictions

The Caselaw Access Project now has scanned images available for download as PDF, with selectable text, for all open-access jurisdictions, including Arkansas, Illinois, North Carolina and New Mexico. To download scanned images by volume, visit our downloads page and browse to the volume you seek:

Through our API and bulk data tools, researchers already have access to metadata and text files produced through OCR of the scanned images. With this new release, we're able to share the scanned images themselves in an enhanced form that enables text selection and search.

For this initial release, scanned images are available only for those jurisdictions that have taken the important step of ensuring that all of their current opinions are published and freely accessible online in an authoritative, machine-readable manner that avoids vendor-specific citation. As always, we're eager to work with other states seeking to take this step toward digital-first publishing. Here's how to get started.

Connecting Data with the Supreme Court Database (SCDB) and Caselaw Access Project

Last week we released an update to the Caselaw Access Project that adds case IDs and citations from the Supreme Court Database (SCDB) to our U.S. Supreme Court case metadata.

This update adds new, parallel citations to cases and makes it easy for people using data from the Caselaw Access Project to also take advantage of this rich dataset made available by the Supreme Court Database (SCDB). This represents one of the major benefits of open data - the ability to connect two datasets to enable new kinds of analysis and insight.

The Supreme Court Database (SCDB) is an outstanding project by Harold J. Spaeth, Lee Epstein, Ted Ruger, Jeffrey Segal, Andrew D. Martin and Sarah Benesh. A key resource in legal data, SCDB offers case-and-justice-specific metadata about every Supreme Court decision. Metadata made available by this resource covers a range of variables, like Majority Opinion Writer, Docket Number, Issue Area, Majority and Minority Votes, and more. To learn more about the Supreme Court Database (SCDB), their documentation is a great place to start.

Here are some ways to work with Supreme Court Database (SCDB) data and Caselaw Access Project.

When viewing an individual case in the Caselaw Access Project, new citations and case IDs from SCDB are now visible in the citations field. Here’s a look!

Example of case citation field, showing: "Brown v. Board of Education, 347 U.S. 483, 98 L. Ed. 2d 873, 74 S. Ct. 686 (1954)".

When we retrieve cases with Caselaw Access Project API, we can see the connection between our case metadata and data made available by the Supreme Court Database (SCDB). Try this example.

Caselaw Access Project API displaying citation metadata for case "Brown v. Board of Education, 347 U.S. 483, 98 L. Ed. 2d 873, 74 S. Ct. 686 (1954)"

You can retrieve cases from CAP Search and the CAP API with a Supreme Court Database (SCDB) ID. Here’s how to do it. In CAP Search, add your SCDB ID to the Citation field and run your search. Here’s an example! Want to do the same in the CAP API? Create an API call to retrieve a case by citation, and add the SCDB ID. Here’s what that looks like:

We’re also making a download available of cases matched from the Supreme Court Database (SCDB) to the Caselaw Access Project as a spreadsheet:

What can we learn with this data? Here’s one example. By using data from the Caselaw Access Project and the Supreme Court Database (SCDB) data together, you can isolate opinions by particular justices, or opinions that involve particular legal issues. This can be the first step to understanding the appellate history of a Supreme Court case. This is just one of the many possibilities that are now available as part of this opportunity to learn new things with case data.

This is our first cut at incorporating external data into the Caselaw Access Project, and there may be bugs we have not yet identified. For example, while we are able to match 28,090 out of 28,347 cases (~99%), there are a few we couldn’t match. We’ll be taking a look at those and updating the data as we go. If you find other errors, as always, reach out to tell us about them.

We’re excited about this update to the Caselaw Access Project and grateful for all the hard work the folks at Supreme Court Database (SCDB) have done to make and to share their data. With this update, we’re excited to see what our community learns and creates with this resource. Working on something new? We’re looking forward to hearing about it.

Some Recent Perma Use

You may have seen links in a number of documents of current interest, including the Trial Memorandum of the U.S. House of Representatives in the Impeachment Trial of President Donald J. Trump (archived at and the Trial Memorandum of President Donald J. Trump (archived at Interestingly, both documents cite Perma links without citing the original URL that Perma archived; generally, you would include both in your citation.

As an exercise, I used Perma's public API to look up the URLs for the Perma links cited in these two documents; here are CSV files listing the 148 links in the House Memorandum (one ill-formed) and the 129 links in the President's memorandum. (Note that both CSV files include duplicates, as some links are repeated in each document; I'm leaving the duplicates in place in case you want to read along with the original documents.)

North Carolina Joins Growing List of Open Access Jurisdictions

Today we're pleased to announce that North Carolina has joined Illinois, Arkansas, and New Mexico as the latest jurisdiction to make all of its appellate court decisions openly available online, in an authoritative, machine-readable format that is citable using a vendor-neutral citation.

As a result of North Carolina taking this important step, the Caselaw Access Project has removed all use and access restrictions from the North Carolina cases in its collection. You now can view or download the full text of all North Carolina cases without restriction. You can read individual cases with the CAP Case Browser or access many cases at once with the CAP API and Bulk Data. Here's an example!

We're delighted and inspired by the work of the North Carolina Supreme Court and the many dedicated professionals on the Court's staff. We hope that many other states will follow North Carolina’s example as soon as possible. Here's how to help make it happen.

The Open Casebook: Creating Casebooks with H2O and the Caselaw Access Project

What if you could create your own casebook with any case ever published? By connecting H2O open casebooks with the Caselaw Access Project, we can change how we read and create casebooks.

In higher education, open textbooks have created new ways to learn, share, and adapt knowledge - and save students money in the meantime. For casebooks that can cost law students hundreds of dollars each, this gives law schools the opportunity to create casebooks to serve their communities.

What do open casebooks look like? From Contracts (Prof. Charles Fried), Criminal Law (Prof. Jeannie Suk-Gersen), Civil Procedure (Prof. I. Glenn Cohen), Torts (Prof. Jonathan Zittrain) and more, open casebooks are one way to create course content to support the future of legal education.

How can you create a new casebook with 6.7 million unique cases from the Caselaw Access Project? Here’s how!

  1. Create your casebook (Here’s more on how to get started).
  2. Select “Add Resource”.
  3. Under “Find Case”, import your case by citation (Example: 347 U.S. 483).
  4. Select the case. You’ve just added it to your casebook! Nice 😎.

With a collection of all published U.S. case law, what casebooks would you create, read, and share? Create your casebook with H2O Open Casebooks and the Caselaw Access Project.