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 graduatedfrequency (GF) approach, which asks about the frequency of alcoholconsumption at mutually exclusive quantity levels (i.e. 12 ormore drinks, at least eight drinks but less than 12, etc.). Methods: Telephone survey of 464 adults aged 18 and older inToronto, Canada, using random digit dialling and computer-assistedtelephone interviewing. Results: Respondents reported higher frequency and volume ofdrinking on the GF compared to overall and beverage-specificquantity–frequency type measures; however, at least 16%of GF responses included double counting on their frequencyestimates using the GF. When these cases were excluded or corrected,differences between the GF and quantity–frequency measuresmostly disappeared. The GF was superior to quantity–frequencymeasures for identifying heavy episodic drinkers. However, theGF had little advantage over the weekly recall method exceptfor identifying very infrequent (i.e. less often than twicea month) heavy drinkers. Conclusions: Because the GF has a highrate of response errors in terms of measuring frequency of alcoholconsumption, other combinations of measures, including alternatemeasures of heavy episodic drinking should be considered.