search across all the following databases:
Data and documentation
Common questions and answers.
Entire collection of data resources.
ACS Data Resease Main
This is the main site for information about the American Community Survey (ACS). The site is reasonably well-organized, but if you have trouble finding something, come back and find it via our annotated links.
Guides and Tutorials
Handbooks for Data Users
The Compass Series provide an overview of the ACS with some specific how-to instructions and/or case studies. There are specific guides for many user groups: general, Congress, the media, state and local governments, researchers, etc. Scroll down the page until you find the guide that best fits your need.
Each guide has a technical appendix at the end with guideance on single year vs multi-year estimates, measures of sampling error, tests of statistical significance. Here is a link to a stand-alone version of the technical appendix.
These are PowerPoint presentations that the Census Bureau uses for training the public about the ACS. Each set of slides comes with very detailed speaker notes.
This is an online tutorail on the ACS - takes an hour to complete
Virtual Tour and Tutorials for the New Release (January 2011) of American FactFinder
This gives you a head start on learning the new features and functions in American FactFinder
Questions and Questionnaires
Subjects Planned for the 2010 Census and the ACS
These links provide the justification for the items included in the 2010 Census (short-form) and the ACS (long-form).
Question by Question Fact Sheets
The fact sheets have ACS question(s), how long the question has been in use, a description of how the federal government uses the data and how those uses translate into community benefits.
ACS Questionnaires - Questionnaire Archive
These are replicas of the questionnaires sent to households. Sometimes questionnaires change across years - new questions or the layout of the questions. These are summarized in:
Unfortunately, this is a tedious way to find out about "new" variables, including the justification for why they have been added or dropped.
ACS: Sample Size, Accuracy, Quality, Comparison
The sample sizes for all published counties and county equivalents starting with the 2007 ACS will only be available in the B98* series of Detailed Tables on American FactFinder (AFF).
Sample size information for years prior to 2007 will remain on the ACS website and will not be added to AFF.
Accuracy of the Data
These documents provide data users with a basic understanding of the sample design, estimation methodology, and accuracy of the data. Note that the "Accuracy" portion is in the right panel of the webpage
Also note that there is a direct link to the Design and Methodology report
Quality of the Data
These quality measures [sample size, response rates, coverage rates, and item allocation rates] are produced annually to accompany each ACS data release and describe the quality of those data. The quality measures are available at national and state levels. Clicking on "definitions" will provide additional information on each of these measures, including why the measure is important and how it was calculated.
Guidance on Comparing ACS data to Other Sources
The Census Bureau encourages users to compare ACS data with data from other sources. This page provides three forms of guidance - general guidance, item-specific guidance, and examples. For all comparisons of differing time periods, users should take into consideration that geographic boundaries for the area of interest may have changed.
Here's a link to the Quick Guide, but for more detail follow the previous link:
Design and Methodology Report &Other Details
Design and Methodology Report
This document describes the basic ACS design and methodology as of the 2007 data collection year. The purpose of this document is to provide data users and other interested individuals with documentation of the methods used in the ACS. Future updates of this report are planned to reflect additional design and methodology changes. This document is organized into 15 chapters. Each chapter includes an overview, followed by detailed documentation, and a list of references.
Technical Appendix from the ACS Compass Products
Data Collection & Processing
This provides a brief summary of interviewing rules, residence rules, data collection procedures, follow-up, etc.
Group Quarters Definitions
Note that these links will be towards the bottom of the page under "Code Lists" and "Subject Definitions."
What the ACS Can Tell us About Mixed Mode Surveys
This is a presentation given by Deborah Griffin, Census Bureau, at a joint SRC/PSC brownbag. It has a great deal of information on the details of the different modes of data collection (mail, phone, in-person); differences in response across the country; mode effects, etc.