American Community Survey

ACS at a Glance

ACS at a Glance
American Community Survey
Data Type National self-report survey
Sample Nationally, State representative Sample
VEHSS Topics Included Visual Function
Years Analyzed 2014, 2015, 2016, 2017
Approximate Size 3 million persons per year

The American Community Survey (ACS), conducted by the United States Census Bureau, is an annual, nationally representative survey that collects and produces information on demographic, social, economic, and housing characteristics of the US population. The ACS serves the nation by providing a consistent and cohesive collection of characteristics that are comparable across all US geographies. The Census Bureau releases the Public Use Microdata Sample (PUMS) files for use by data users who want to create custom tables that are not available through summary ACS data products such as the American Fact Finder.

ACS PUMS was selected for inclusion in the VEHSS system because of its representative and robust national and state sample, and because information contained in the ACS supports stratification by the key demographic and geographic variables of interest to the VEHSS system.

Sample Design

The Census Bureau selects a random sample of addresses to be included in two separate samples that together constitute the ACS: housing unit (HU) addresses and residents of group quarters (GQ) facilities (e.g., college residence halls, residential treatment centers, skilled nursing facilities, group homes, military barracks, correctional facilities, workers’ dormitories, and facilities for people experiencing homelessness). These samples are drawn from the Census Bureau’s Master Address File (MAF), an inventory of living quarters and nonresidential units in the United States and Puerto Rico. Independent HU address samples are selected for each of the counties and county equivalents in the United States, as well as for each of the municipalities in Puerto Rico. GQ resident samples are independent state-level samples.

As of 2011, the size of the HU sample selected is approximately 3.54 million. Interviews are conducted monthly, and no HU address or small GQ facility residents are eligible to be in the sample more than once in a 5-year period. Residents of large GQ facilities are eligible to be sampled every year.[1]

ACS PUMS files consist of sub-samples of ACS HU and GQ respondents. These files are designed to include one percent of both the HU and GQ populations estimated by the full ACS.  HU and GQ PUMS samples were constructed separately, and sampling intervals for each are calculated to yield target sample sizes at the state level.[2]

Data Collection Procedures:

ACS data are collected in one of four modes: internet, mail, telephone, and personal visit. For most HUs, mailed invitations to participate via internet are extended initially. If no response is received, this is followed by invitations to participate via mail, telephone, or personal visit, in that order, based on participant response or non-response to each previous option. Data are collected from GQ residents via personal interview only. For sampled HUs, information is collected for all residents living in the household. The participation rate in 2014 was 96.7% for people living in HUs and 95.9% for people living in GQs. Participation rates in 2015 were 95.8% and 95.3% for HU and GQ residents, respectively.

Analysis Overview

For the VEHSS team, NORC estimated the prevalence rate and sample size for each survey instrument selected for inclusion. We analyzed the 2014 and 2015 PUMS files separately. The prevalence rate was defined as the number of people who gave an affirmative response to the question divided by the total number of respondents who gave an affirmative or negative response and multiplied by 100 for presentation in percentage format. Estimates that were based on a sample size of less than 30 and/or with a relative standard error greater than 30% were suppressed.

A detailed description of the analytical steps is described in the report “VEHSS Survey Analysis Plan [PDF – 480 KB]external icon.”  Full analysis documentation is included in the “VEHSS ACS Data Report [PDF – 359 KB]external icon.”

Variables Analyzed in VEHSS:

ACS contains a single question relevant to VEHSS: “Is this person blind or does he/she have serious difficulty seeing even when wearing glasses?” This question, which was first fielded in 2008, was categorized under the VEHSS ‘Visual Function‘ topic and ‘Difficulty Seeing with Glasses’ category. Table 1 presents additional details about the question, including the ACS variable name, the year(s) survey data are available, the survey question, and the response options.

Table 1. Overview of ACS Variables Included in VEHSS

Iris Registry
VEHSS Indicator Topic VEHSS Indicator Category ACS Variable Name ACS Question Text Years Available
Response Options
Visual Function Difficulty Seeing with Glasses DIFFEYE Is this person blind or does he/she have serious difficulty seeing even when wearing glasses? 2008-2016
  • 1 Yes
  • 2 No

Additional information about ACS can be found on the U.S. Census Bureau [PDF – 10.1 MB]external icon website.

[1] American Community Survey design and methodology. Washington, DC: US Census Bureau; 2014. [PDF – 607 KB]external icon. Accessed September 01, 2016.

[2] PUMS accuracy of the data. Washington, DC: US Census Bureau; 2015. [PDF – 2.5 MB]external icon. Accessed September 01, 2016.