About Adult Substance Misuse Data

Tracking adult substance use involves collecting data about the number of individuals who reported substance use while participating in the Behavioral Risk Factor Surveillance System (BRFSS) survey.

This page provides general information about adults’ use of alcohol through measures developed by the Iowa Public Health Tracking program. Contact Us for more information about these data.

Information on this page:

What is the source of the data?

  • The substance use data displayed here are collected through the Behavioral Risk Factor Surveillance System (BRFSS). BRFSS is the nation’s premier system of telephone surveys that collect state-level data about health risk behaviors, chronic health conditions, and use of clinical preventive services among adult U.S. residents.

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How does BRFSS collect data?

  • BRFSS invites a randomly selected sample of Iowan adults to participate in the telephone survey. Recent surveys have included both adults who have landline telephones and cell phone users, and have between 6,000 and 7,700 participants. All responses are weighted to the entire Iowan population so that weighted results are intended to capture the experience of the entire state.

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Which questions were used to collect data on adult substance use?

  • Three questions on substance use are presented here from BRFSS.
    The first question asked respondents, “During the past 30 days, how many days per week or per month did you have at least one drink of any alcoholic beverage such as beer, wine, a malt beverage or liquor?” Those who answered "at least once" were counted as having had an alcoholic beverage.
  • The second question asks respondents, “One drink is equivalent to a 12-ounce beer, a 5-ounce glass of wine, or a drink with one shot of liquor. During the past 30 days, on the days when you drank, about how many drinks did you drink on the average?”
  • The third question asks respondents, “Considering all types of alcoholic beverages, how many times during the past 30 days did you have (5 for men, 4 for women) or more drinks on an occasion?”
  • Those who responded "No" or "None" were not counted as having at least one drink of an alcoholic beverage.

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What time period was the data collected?

  • The alcohol questions regarding alcoholic beverages were asked in the BRFSS Core section every year from 2011-2017.

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Can I compare pre-2011 BRFSS data to post-2011 BRFSS data?

  • No. Data from 2011 and later should not be compared to data from before 2011 due to changes in data collection and analysis methodology. Earlier versions of the BRFSS survey only contacted people with landline telephones. Beginning in 2011, BRFSS changed the collection methodology to include cell phones in its sampling frame. In addition, a new method for weighting the sample called iterative proportional fitting or raking was introduced. This methodology better allows data for population subgroups that are underrepresented in the sample to be more accurately represented in weighted estimates. The raking method allows more demographic variables to be used in creating sample weights leading to more accurate estimates.

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Where can I find more technical information about the data?

  • To explore technical information and to review the annual reports, please visit the IDPH BRFSS website.