What Is Moderate Drinking?

Alcohol Research & Health, Wntr, 1999 by Mary C. Dufour

A study's proposed research goals dictate the particular measurement approach. Furthermore, techniques that are ideally suited for one population subgroup may not work equally well for other subgroups (e.g., teenagers versus senior citizens). Consequently, scientists conducting large and expensive population-based surveys to answer multiple research questions and elucidate drinking behavior in diverse population subgroups must weigh many factors in deciding which alcohol-consumption measures will best meet their needs. The accuracy and validity of the results regarding the quantity (i.e., number of drinks), frequency, and volume (i.e., drink size) of alcohol consumption depend primarily on two factors: the survey methodology and the assessment mode used.

Survey Methodology

The effectiveness of an assessment instrument (i.e., survey questionnaire) in accurately determining drinking patterns is influenced by the way in which the survey questions are phrased, the order in which the questions are arranged, and the manner in which the answers are combined into a summary index (i.e., converted into a single measure for analysis purposes - for example, "moderate" drinker). The types of survey questionnaires most commonly used to measure alcohol consumption fall into five categories: (1) frequency measures, (2) quantity-frequency (QF) measures, (3) graduated frequency measures, (4) short-term recall methods, and (5) diary methods.

Another technique for assessing alcohol consumption is the timeline followback (TLFB) method (Sobell and Sobell 1995). The TLFB is a structured interview in which participants receive calendar-based memory cues to assist them in constructing a chronological report of their alcohol use. Although the procedure is widely employed in research on the efficacy of alcoholism treatment, the required interviews are highly individualized and, hence, generally impractical for use in large-scale population-based surveys.

Frequency measures query the respondent on his or her typical drinking frequency in a given timeframe (e.g., the past year), based on various predetermined categories from which to choose (e.g., "never," "once a month," "once a week," or "everyday"). Because these frequency measures do not assess the alcohol amount consumed on each drinking occasion, they do not allow researchers to calculate a person's average or total volume of alcohol consumption.

QF measures query the respondent on both drinking frequency and average quantity consumed per occasion, thereby providing a measure of the total alcohol amount consumed. QF measures currently may be the most widely used instruments with which to measure drinking in most countries, including the United States. Generally, the quantity question asks for the typical number of drinks consumed per occasion, providing the respondent with some definition of a drink (e.g., one 12 oz can or bottle of beer) on which to base his or her answer. A popular variant of the QF methodology is represented by self-administered, semiquantitative food-frequency questionnaires, which assess the consumption of different foods (see, for example, the questionnaire developed by Willett and colleagues [1988]). For example, a simple frequency questionnaire would ask, "How often do you drink milk?" A semiquantitative food frequency questionnaire, however, would ask, "How often do you drink a glass of milk?" and may even define the size (e.g., 8 oz). In some QF surveys, respondents are asked how often and how much, on average, they consumed different types of alcoholic beverages over the past year. Those surveys generally include specific definitions of standard drink sizes for each beverage type assessed.