The Congressional Research Service ( CRS ), known as Congress's think tank , is a public policy research arm of the United States Congress . As a legislative branch agency within the Library of Congress , CRS works primarily and directly for Members of Congress, their Committees and staff on a confidential, nonpartisan basis.
Its staff of approximately 600 employees includes lawyers, economists, reference librarians, and social, natural, and physical scientists.  In fiscal year 2016, CRS was appropriated a budget of roughly $106.9 million by Congress. 
CRS is joined by two major congressional support agencies. The Congressional Budget Office provides Congress with budget-related information, reports on fiscal, budgetary, and programmatic issues, and analyses of budget policy options, costs, and effects. The Government Accountability Office assists Congress in reviewing and monitoring the activities of government by conducting independent audits, investigations, and evaluations of federal programs. Collectively, the three agencies employ more than 4,000 people. 
CRS reports are widely regarded as in depth, accurate, objective, and timely, but as a matter of policy they are not made available to members of the public by CRS, except in certain circumstances.  There have been numerous attempts to pass legislation requiring all reports to be made available online but none have been enacted. Instead, the public must request individual reports from their Senators and Representatives in Congress, purchase them from private vendors, or search for them in various web archives of previously released documents.
In 1914, Senator Robert La Follette Sr. and Representative John M. Nelson , both of Wisconsin, promoted the inclusion in the legislative, executive, and judicial appropriations act of a provision directing the establishment of a special reference unit within the Library of Congress. Building upon a concept developed by the New York State Library in 1890, and the Wisconsin Legislative Reference Library in 1901, they were motivated by Progressive era ideas about the importance of the acquisition of knowledge for an informed and independent legislature.  The move also reflected the expanding role of the librarian and the professionalization of the profession.  The new department was charged with responding to congressional requests for information.  The legislation authorized the Librarian of Congress, Herbert Putnam , to “employ competent persons to prepare such indexes, digests, and compilations of laws as may be required for Congress and other official use...” (The intent behind the creation of the agency can be derived from U.S. Senate, Committee on the Library, Legislative Drafting Bureau and Reference Division, 62d Cong., 3d sess., 1913, S. Rept.1271.)
Renamed the Legislative Reference Service and given a permanent authorization with the Legislative Reorganization Act of 1946 , it assisted Congress primarily by providing facts and publications and by transmitting research and analysis done largely by other government agencies, private organizations, and individual scholars. 
The Library of Congress, the home of CRS, had experimented during the 1940s with unrestricted publication Public Affairs Bulletins , which were produced by staff of the Legislative Reference Service, and devoted to various public policy issues. They were promoted by Archibald MacLeish , the Librarian of Congress, and, among other topics, addressed timely policy issues, such as American national defense. About 100 Public Affairs Bulletins were generated before congressional appropriators ended their production in 1951.
The renaming under the Legislative Reorganization Act of 1970 reflected the service's changing mission:  This legislation directed CRS to devote more of its efforts and increased resources to doing research and analysis that assists Congress in direct support of the legislative process.
When the Congressional Research Service Review was launched in 1980, it continued for a little more than a decade before congressional appropriators, once again, invoked fiscal closure. The Review, which was published ten times a year and available to the public by subscription, offered original analytical articles, summaries highlighting CRS research products, and other kinds of assistance to the congressional community.
As inquiries increased from 400,000 questions per year in 1980 to 598,000 in 2000, CRS sought to prepare itself for future challenges, initiating an organizational realignment in 1999. The realignment, which has required extensive relocation of staff and the design of more efficient workstations, was intended to promote improved communication within CRS and increase the service's ability to focus on legislative deliberations of Congress by applying its multidisciplinary expertise to public policy issues in user-friendly, accessible formats when Congress needs assistance. 
CRS offers Congress research and analysis on all current and emerging issues of national policy.  CRS offers timely and confidential assistance to all Members and committees that request it, limited only by CRS’s resources and the requirements for balance, nonpartisanship and accuracy. 
CRS makes no legislative or other policy recommendations to Congress; its responsibility is to ensure that Members of the House and Senate have available the best possible information and analysis on which to base the policy decisions the American people have elected them to make.  In all its work, CRS analysts are governed by requirements for confidentiality, timeliness, accuracy, objectivity, balance, and nonpartisanship.
CRS services are not limited to those that relate directly to enacting new laws. For example, CRS attempts to assess emerging issues and developing problems so that it will be prepared to assist the Congress if and when it becomes necessary. Although it rarely conducts field research, CRS assists committees in other aspects of their study and oversight responsibilities. In addition, it offers numerous courses, including legal research seminars and institutes on the legislative process, the budget processes, and the work of district and state staff. At the beginning of each Congress, CRS also provides an orientation seminar for new Members. 
CRS does not conduct research on sitting Members or living former Members of Congress, unless granted specific permission by that Member or if that Member is nominated by the President for another office. 
CRS is now divided into six interdisciplinary research divisions, each of which is further divided into subject specialist sections. The six divisions are: American Law; Domestic Social Policy; Foreign Affairs, Defense and Trade; Government and Finance; Knowledge Services; and Resources, Science and Industry. 
The six research divisions are supported in their work by five “infrastructure” offices: Finance and Administration, Information Management and Technology, Counselor to the Director, Congressional Information and Publishing, and Workforce Management and Development. 
Overview of services
Responses to Congressional requests take the form of reports, memoranda, customized briefings, seminars, videotaped presentations, information obtained from automated databases, and consultations in person and by telephone. 
CRS "supports the Members, committees, and leaders of the House and Senate at all stages of the legislative process": 
- Ideas for legislation . At the preliminary stage, members may ask CRS to provide background information and analysis on issues and events so they can better understand the existing situation and then assess whether there is a problem requiring a legislative remedy. This assistance may be a summary and explanation of the scientific evidence on a technically complex matter, for example, or it may be a collection of newspaper and journal articles discussing an issue from different perspectives, or a comparative analysis of several explanations that have been offered to account for a generally recognized problem. CRS also identifies national and international experts with whom Members and staff may consult about whatever issues concern them and sponsors programs at which Members meet with experts to discuss issues of broad interest to Congress. 
- Analyzing a bill . If a Member decides to introduce a bill, CRS analysts can assist the legislator (or their staff) in clarifying the purposes of the bill, identifying issues it may address, defining alternative ways for dealing with them, evaluating the possible advantages and disadvantages of each alternative, developing information and arguments to support the bill, and anticipating possible criticisms of the bill and responses to them. Although CRS does not draft bills, resolutions, and amendments, its analysts may join staff consulting with the professional draftsman within each chamber’s Office of the Legislative Counsel as they translate the Member’s policy decisions into formal legislative language. Members and committees also can request CRS to help them assess and compare legislative proposals, including competing bills introduced by Members and proposals presented by executive branch officials, private citizens and organizations. CRS can assess the intent, scope, and limits, of the various proposals. 
- During committee and floor consideration, CRS can assist Representatives and Senators in several different ways, in addition to providing background information to assist Members in understanding the issues a bill addresses. CRS attorneys can help clarify legal effects the bill may have. CRS policy analysts can work with Members in deciding whether to propose amendments and then in making certain that their amendments are designed and phrased to achieve the desired results. CRS also can help Members prepare for the debate by providing data and other information that they can use to support the positions they have decided to take. 
- Hearings . When a subcommittee selects a bill (or several bills on the same subject) for serious attention, it usually begins by conducting public hearings on one or more days at which executive branch officials, other Members of Congress, representatives of private organizations, and even individual citizens present their views on the bill’s merits. CRS analysts can assist in this process by providing background information and reports, presenting a preliminary briefing to Members or staff, identifying potential witnesses, and suggesting questions that Members may consider asking the witnesses.
- Subcommittee or committee votes . After the hearings on a bill, the subcommittee or committee meets to debate and vote on amendments to it. If requested, CRS staff may attend these meetings to serve as a nonpartisan source of expert information available to all Members. If the subcommittee and then the full committee conclude that new legislation is needed, they report a bill to the House or Senate for all its Members to consider. The committee also submits a written report that explains the background for its decision, analyzes the purposes and effects of each major provision of the bill, and includes other information, such as predictions about the cost of implementing it, that help other Members decide whether they should support the bill. CRS specialists may assist the committee’s staff in preparing some sections of this report, although cost estimates are developed by the Congressional Budget Office.
- Parliamentary procedure . CRS staff can clarify the legislative procedures of the House and Senate, assisting Members and staff in understanding the effects of these procedures and how Members can use the procedures to promote their own legislative goals.
- Conference committees . CRS analysts can contribute to this last stage of the legislative process by helping identify the issues to be resolved, by clarifying and comparing the positions of the two houses on each issue, and by identifying different ways in which the legislative disagreements could be resolved.
CRS also performs several functions that support Congressional and public understanding of the legislative process and other issues.
- Bill Summaries . Since 1935 the Legislative Analysis and Information Section (formerly "Bill Digest") of CRS has had statutory responsibility for preparation of authoritative, objective, nonpartisan summaries of introduced public bills and resolutions and maintenance of historical legislative information. Detailed revised summaries are written to reflect changes made in the course of the legislative process. This CRS office also prepares titles, bill relationships, subject terms, and Congressional Record citations for debates, full texts of measures, and Member introductory remarks. The bill summaries are released to the public via THOMAS , the Library of Congress's online database. 
- Constitution Annotated . The American Law Division of the Congressional Research Service prepares the Constitution of the United States of America—Analysis and Interpretation (popularly known as the Constitution Annotated),  a continuously updated legal treatise that explains the U.S. Constitution as it has been interpreted by the U.S. Supreme Court.
Current Members of Congress and their offices may access the CRS website (www.crs.gov) and CRS's Legislative Information Service (LIS) website (www.congress.gov). The two sites are the most comprehensive and integrated sources of information regarding workings of the federal government, and are arguably the best sources of information regarding the legislative process of the United States. 
These sites provide all information necessary to become informed about any aspect of government. They also have the information needed to keep up-to-the-minute on most legislation including information from past bills similar to the current legislation; historical information about the legislation; biographical data about the Members who introduced it; the ability to track the legislation as it moves through committee hearings to the Floor; and links to information about the legislation in the Congressional Record, Floor and committee schedule information, and the Federal Register.
Neither of these websites is available to the public. In order to prevent public access to the websites, CRS has erected an elaborate firewall to keep the public out. Taxpayers are only allowed access to THOMAS (thomas.loc.gov). In fact, when the public tries to access the LIS, they are automatically forwarded to THOMAS without warning. 
www.crs.gov . The CRS website provides CRS publications on current legislative issues, electronic briefing books, information on the legislative and budget processes, a searchable database of all CRS products, and other information about Congressional procedures and activities.
www.congress.gov . The LIS website is specifically designed to track legislation and legislative activity. According to the CRS, "The LIS ... provides bill summary and status, full text of legislation and public laws, full text of committee reports, hearings, and other documents, and the Congressional Record for the current and earlier Congresses. The system also gives (and is searchable by) committee, sponsorship, and cosponsorship; identification of identical bills; and other information." The LIS varies substantially from the system which is available to the public at the Library of Congress' THOMAS website (thomas.loc.gov). In fact, CRS has a special page detailing the enhanced capabilities of the restricted LIS website over the public THOMAS website.
The following is CRS's comparison of the LIS (www.congress.gov) with THOMAS (thomas.loc.gov): 
|Service||Legislative Information System||Thomas|
|Who Can Use It||Available to the public. (Previously only available to Congress, including state and district offices, and legislative support agencies. Some features listed below may no longer be available.)||Available to the public.|
|Best Used For||Finding the most complete legislative information for congressional staff or for a Member; obtaining information, using databases, and linking to pages that are not available to the public on THOMAS. Should not be used for making links from Member or committee home page (since the public cannot access LIS).||Working with constituents; making links from Member or committee home pages; making printouts that are to be sent to constituents.|
|Commercial Databases||Links to databases that have been licensed for use by House and Senate staff, such as National Journal and the AP Newswire. Links from the status of a bill to National Journal markups.||No links to commercial databases.|
|CRS Reports||Links from Bill Summary & Status display to CRS reports related to a bill. Ability to search all CRS reports via the CRS Home Page; these products can be searched, displayed, and printed.||No CRS reports are available to the public.|
|Restricted links||Links to restricted Capitol Hill Web sites such as the House Intranet, Senate Webster, and Senate amendment tracking system.||No links to restricted Capitol Hill Web sites.|
|Floor & Committee Schedule Information||Links to Capitol Hill and outside sources of floor and committee schedule information, selected to be of most use to congressional staff.||Minimal links to floor and committee schedule information.|
|Advanced search capabilities||Special advanced search capabilities, providing Boolean searching (and, or, not), word proximity searching (quotes to indicate phrases, adj/l, near/l), and other features.||Only basic search capabilities.|
|Saved searches and email alerts||The ability to save searches and to request daily email alerts of new items added to databases that meet the search criteria.||No ability to save searches or request email alerts.|
Document types include CRS Reports, appropriations Reports (usually released as a Long Report), and Congressional distribution memoranda. 
The most commonly requested CRS product is the general congressional distribution reports, known as "CRS Reports". The purpose of a report is to clearly define the issue in the legislative context.  The types of CRS reports include Issue Briefs (IB), Research Memos (RM), and Reports, which appear in both Short (RS) and Long (RL) formats. 
Over 700 new CRS reports are produced each year and made available to Congressionals at www.crs.gov.  566 new products were prepared in Fiscal Year 2011.  Nearly 7,800 are in existence as of the end of 2011. 
Other than a passing generic reference to "reports" in its statutory charter, CRS has no mandate for these products. They are created in the context of the overall mission of CRS to provide research support to Congress.
The reports may take many forms, including policy analysis, economic studies, statistical reviews, and legal analyses. 
The CRS has written:  "CRS may incorporate preexisting material in its written responses to congressional requests. Although such material is often from public domain sources, in certain instances the material, appropriately credited, may be from copyrighted sources. To the extent that the material is copyrighted, CRS either: obtains permission for the use; [Footnote: Although CRS obtains permission to reproduce certain copyrighted works, the permissions are generally based on legislative use and the expectation that dissemination is limited to Members of Congress.] considers its information-gathering function protected by the speech or debate clause; or believes that the use falls under the ' fair use ' doctrine of the Copyright Act as applied in the context of the legislative process."
Public access to CRS Reports
While CRS products are already available electronically to members of Congress, Congressional committees, and CRS's sister agencies (CBO and GAO) through the internal CRS Web system, there is no official public access,  except in certain circumstances.  For example, specifically identified individual products have been furnished to executive and judicial branch officials and employees, and state and local government officials. Products have been distributed when it has been deemed to enhance CRS service to Congress. Products have also been furnished to members of the media and foreign embassies on request, but only if the requester can make specific reference to the product number or title of the report. On occasion, CRS researchers have provided reports to non-congressional sources including individual researchers, corporations, law offices, private associations, libraries, law firms, and publishers.
Only Members and their staffs can place requests and attend most seminars. While some CRS research and reports may reach the American public, dissemination is at the discretion of congressional clients,  except as described above.
Many are available; sources are listed in the external links section below. As with other documents produced by the U.S. Government, the documents are in the public domain in the United States, and not subject to copyright.