The Superintendent of Documents, under the direction of the Public Printer, is responsible for taking the Biennial Survey of Depository Libraries, required by 44 U.S.C. Section 1909. The Biennial Survey provides GPO with important information concerning the conditions of both individual depository libraries and the depository library program as a whole. This data is used to administer the program and to assist in the assessments of the conditions and services of depository libraries.

All Depository Libraries are legally required to complete this survey.

In the past the Biennial Survey data was used to supplement the information obtained by in-depth inspections of Federal Depository libraries, conducted every 3-7 years. Later inspections were replaced by GPO's evaluation of self studies submitted by depository libraries. At all times, past and present, the Biennial Survey has been an important tool to help GPO evaluate individual depository libraries and the program as a whole, either as a stand tool or as a supplement to other evaluation techniques.

GPO maintains Biennial Survey information with the official records of each depository. This information should also be kept by each depository library and passed on to successive depository staff members. Likewise each Regional library can use Biennial Survey information for the depositories under their purview. Since 1997 GPO has posted the reports and data files from each Biennial Survey.

GPO has developed the Biennial Survey in consultation with the Depository Library Council and comments from other members of the Federal Depository Library Program (FDLP) community. Recent Biennial surveys have included a more or less standard core group of questions that allows for analysis across surveys. To that core group of questions, new questions are added and/or some old question deleted as necessary for each new survey. The 2007 Biennial Survey included new questions in the area of public access, collection strengths, and specializations.