Methodology

The Community Health Survey (CHS) has been conducted annually by the New York City Department of Health and Mental Hygiene since 2002. Data collected from the CHS are used to better understand the health and risk behaviors of New Yorkers and to track key indicators over time.

TARGET POPULATION
The target population of the CHS includes non-institutionalized adults aged 18 and older who live in a household with a landline telephone in New York City (the five borough area). Starting in 2009, adults living in households with only cell phones have also been included in the survey.

HEALTH TOPICS
Most years the CHS includes approximately 125 questions, covering the following health topics: general health status and mental health, health care access, cardiovascular health, diabetes, asthma, immunizations, nutrition and physical activity, smoking, HIV, sexual behavior, alcohol consumption, cancer screening and other health topics. A core group of demographics variables are included every year to facilitate weighting and comparisons among different groups of New Yorkers.

SAMPLING
The CHS uses a stratified random sample to produce neighborhood and citywide estimates. Neighborhoods are defined using the United Hospital Fund's (UHF) neighborhood designation, which assigns neighborhood based on the ZIP code of the respondent. New ZIP codes have been added since the UHF's were originally defined. There are 42 UHF neighborhoods in NYC. However, to avoid small sample sizes for CHS estimates, UHF estimates are generally collapsed into 34 UHFs/groups.

Starting in 2009, a second sample consisting of cell-only households with New York City exchanges was added. This design is non-overlapping because in the cell-only sample, adults living in households with landline telephones were screened out.

A computer-assisted telephone interviewing (CATI) system is used to collect the survey data. The CHS sampling frame was constructed with a list of telephone numbers provided by a commercial vendor. Upon agreement to participate in the survey, one adult is randomly selected from the household to complete the interview.

Interviewing is conducted in a variety of languages. Every year, the questionnaire is translated from English into Spanish, Russian, and Chinese. Some years, live translation services are provided by Language Line (including Hindi, Arabic, Farsi, and Haitian Creole). Typically, data collection begins in March of the study year and ends in December. The average length of the survey is 25 minutes.

LIMITATIONS
The survey sampling methodology does not capture the following groups: households without any telephone service and (prior to 2009) households that only have a cell phone. The CHS also excludes adults living in institutional group housing, such as college dormitories.

SAMPLE SIZE, RESPONSE AND COOPERATION RATES
The sample size (completed interviews), the response rate and the cooperation rate are provided for each year of the survey in the table below.

Response and cooperation rates are measurements of overall survey participation among those sampled. More specifically, the Cooperation Rate is defined as the number of those who participated in the survey, divided by the number of individuals in the sample who were contacted and identified as eligible.The Response Rate is a more conservative measure and is defined as the number of all individuals who are known to be, or are likely to be, eligible.

There are multiple and changing ways to calculate these rates, including ways to combine survey participation rates from landline and cellular telephone samples. The NYC Health Department follows the Standard Definitions published by the American Association for Public Opinion Research (AAPOR), currently in its 9th edition. When describing survey participation rates for the CHS, the Health Department generally reports AAPOR’s Response Rate #3 and Cooperation Rate #3 (see Table). Response Rate #3 assumes that some portion of the numbers with unknown eligibility are in fact ineligible and are therefore removed from the denominator. Information from cases with known eligibility (either known eligible or known ineligible) is used to estimate the percentage of unknown eligible cases that are ineligible.

You can get full disposition reports for 2015 and 2016 (PDF) and combined landline and cell phone survey participation rates using the most recent AAPOR definitions. You can also get disposition reports for 2009-2016 (PDF) using earlier participation rate formulas, as well as full disposition reports for 2004-2008 (PDF).

Community Health Survey Participation Rates
CHS survey participation rates are based on Standard Definitions established
by the American Association for Public Opinion Research (AAPOR).
Year Analytic Sample Response Rate
(AAPOR#3)
Cooperation Rate
(AAPOR#3)
2002 9,674 36.0% 69.0%
2003 9,802 44.2% 63.3%
2004 9,585 29.0% 62.5%
2005 9,818 38.7% 79.3%
2006 9,714 35.8% 90.7%
2007 9,554 32.8% 90.4%
2008 7,554 33.3% 80.7%
Starting in 2009, cell phone interviews were added. Landline and cell sample rates were combined per AAPOR Cell Phone Task Force Report (2010).
2009 9,934 37.7% 89.4%
2010 8,665 39.0% 89.4%
2011 8,792 40.0% 89.1%
2012 8,797 39.1% 86.6%
2013 8,698 39.5% 88.7%
2014 8,562 40.5% 88.9%
Rates revised per AAPOR Standard Definitions 9th edition (2016). Unrevised rates shown in parentheses for comparison.
2015 10,172 17.4% (44.3%) 84.2% (89.6%)
2016 10,000 17.3% (42.5%) 85.3% (90.2%)

DATA ANALYSIS
In order to appropriately analyze CHS data, a weight is applied to each record. The weight consists of an adjustment for the probability of selection (number of adults in each household / number of residential telephone lines), as well as a post-stratification weight. The post-stratification weights are created by weighting each record up to the population of the UHF neighborhood, while taking into account the respondent's age, gender and race. Starting in 2009, responses were also weighted to account for the distribution of the adult population comprising three telephone usage categories (landline only, landline and cell, cell only) using data from the 2008 New York City Housing and Vacancy Survey.

If you need assistance with the data, wish to suggest additional variables to be added, or have additional questions about the survey's methodology, please send an email to survey@health.nyc.gov.

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