Over recent years, researchers have heeded the call for improved measures of alcohol consumption and have begun to develop more sophisticated methodologies to assess actual use for both general populations (Dawson, 2003; Kerr, Greenfield, Tujague & Brown, 2005; Martin & Nirenberg, 1991; Midanik, 1982; Miller, Heather & Hall, 1991; Williams, Proudfit, Quinn & Campbell, 1994; Wilson, 1981) and specialized populations, such as pregnant and parenting women (Ernhart, Morrow-Tlucak, Sokol & Martier, 1988; Russell, Chan & Mudar, 1997). For example, an earlier study with uninsured pregnant urban women found that when drink size was considered, average daily volume during pregnancy increased to the risk level for fetal alcohol syndrome (Kaskutas, 2000). This article offers further evidence that drink size should be an important element in assessing potential risk. We focus specifically on an insured population of childbearing-aged females identified as at-risk for drinking during pregnancy by their prenatal care provider.
Historically, a common practice in national survey research (and a practice often used in smaller clinical studies) has been to instruct respondents to report the quantity and frequency of their alcohol intake over some reference period (Greenfield, 2000; Room, 1990). Alcohol use questions are usually prefaced with a definition of a "standard drink;" for example, "a 12-ounce can of beer, a 4-ounce glass of wine or a 1 -ounce shot of liquor" (Alcohol Research Group, 1964-2005; Greenfield, Midanik & Rogers, 2000; Stockwell, Donath, Cooper-Stanbury, Chikritzhs, Catalano & Mateo, 2004), or "a can or bottle of beer, a glass of wine or a wine cooler, a shot of liquor, or a mixed drink with liquor in it" (Office of Applied Studies, 2005). In this case, respondents are required to make quick mental translations to estimate the actual number of "standard drinks" they drink based on the size and alcoholconcentration across all beverages consumed. Other surveys ask respondents to report the number of ounces in their typical drinks for specific beverages (National Institute on Alcohol Abuse and Alcoholism, 2004). Both methods assume that respondents can conceptualize how much a fluid ounce is, an assumption challenged by a growing number of studies showing otherwise (Graves, Kaskutas & Korcha, 1999; Stockwell, et al., 2004; Wansink & van Ittersum, 2005; White, Kraus, Flom, Kestenbaum, Mitchell, Shah, et al., 2005).
To achieve more accurate consumption estimates, researchers have responded in innovative ways, for example, by asking respondents to designate their usual pour level for drinking vessels depicted in life-size photographs (National Institute on Alcohol Abuse and Alcoholism, 2004); or from a selection of actual glasses, bottles, and cans augmented by an array of vessel photographs (Kaskutas & Graves, 2000; Russell, Marshall, Trevisan, Freudenheim, Chan, Markovic, et al., 1997); or by asking respondents to first pour liquid into the glass they usually use for a particular beverage and then having them pour the liquid into a measuring beaker (Banwell, 1999; Carruthers & Binns, 1992; Kerr et al., 2005; Lemmens, 1994). These methods consistently reveal that actual alcohol consumption is underestimated (especially for higher ethanol content beverages and drinks that are poured from larger containers) such that standard drinks should be recalculated using mark-ups that reflect this under-reporting.
Table 1 displays recommended mark-ups for published studies that have looked specifically at drink size. These mark-ups appear to be culturally and demographically influenced. Reviewing across these studies, we found suggested mark-ups ranging from 1.25 for beer, 1.95 for wine, and 2.0 for spirits among drinkers ages 12 and older in New Zealand (Fryer, Kalafatelis, McMillen & Palmer, 2004); around 1 .04 for wine, 1.14 for fortified wine, and 1.26 for spirits among at-home Dutch drinkers (Lemmens, 1994); 1. …