Problems with the graduated frequency approach to measuring alcohol consumption: results from a pilot study in Toronto, Canada.

AIMS To evaluate advantages and disadvantages of the graduated frequency (GF) approach, which asks about the frequency of alcohol consumption at mutually exclusive quantity levels (i.e. 12 or more drinks, at least eight drinks but less than 12, etc.). METHODS Telephone survey of 464 adults aged 18 and older in Toronto, Canada, using random digit dialing and computer-assisted telephone interviewing. RESULTS Respondents reported higher frequency and volume of drinking on the GF compared to overall and beverage-specific quantity-frequency type measures; however, at least 16% of GF responses included double counting on their frequency estimates using the GF. When these cases were excluded or corrected, differences between the GF and quantity-frequency measures mostly disappeared. The GF was superior to quantity-frequency measures for identifying heavy episodic drinkers. However, the GF had little advantage over the weekly recall method except for identifying very infrequent (i.e. less often than twice a month) heavy drinkers. CONCLUSIONS Because the GF has a high rate of response errors in terms of measuring frequency of alcohol consumption, other combinations of measures, including alternate measures of heavy episodic drinking should be considered.