Question detail and complexity

A number of studies have investigated how the types of questions participants are asked influences reported consumption. Under-reporting is assumed to be prevalent when questions used achieve relatively low consumption estimates. Where reported consumption is higher, under-reporting is thought to be less of a problem. Quantity-frequency (QF) questions, which ask about how much alcohol is consumed, and how often, are common in social surveys.

Graduated-frequency (GF) questions ask the frequency consumption of, for example, more than 12 drinks, and working downwards to 3-4 and 1-2 drinks (84). These often give greater consumption volumes than QF questions (84). Although this is thought to be more accurate, a participant whose usual consumption is above the mid-point of the quantity level has their consumption recorded as this mid-point, and is under-reporting (84). Such participants would benefit from being asked the maximum number of drinks on an occasion (84).

Rehm’s 1998 review compared questionnaire designs, finding that drinking diaries recorded the highest consumption, followed by GF questions, QF questions, then weekly recall (43).

Questions can be beverage-specific, or be about all types of alcohol combined. Beverage-specific questions or questions about Beverage-specific occasions lead to higher consumption estimates (43), so are considered to be more accurate. Another review, published in 1999 by Feunekes, reviewed 33 methodological papers published after 1984 and compared five different question types (QF, extended QF, retrospective diary, prospective diary, and 24-hour recall) (85). The mean level of alcohol intake was found to differ by about 20% between these methods (85).

Beverage-specificity tended to increase consumption by around 20% (85). Where a prospective drinking diary (PD) is used to record alcohol consumption, quantity estimates are often higher than those obtained by standard survey questionnaire estimates such as QF (1). Table 2.2

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summarises the findings of two review articles and other relevant studies identified in the systematic review. The majority of the studies conducted have used a test-retest methodology;

where the same participants are asked twice about their alcohol consumption, using two different measures or instruments. Where intra-individual comparisons are made the two measures are not always asking about the same time period. Therefore it is not the individual difference between the two (or more) measures, but rather the difference between the two measures on an aggregate level that is of interest. Studies have been conducted worldwide and over a long period of time. There is no clear pattern in the difference between QF, GF and RR across the studies reviewed. However, the studies reviewed generally find beverage-specificity to be beneficial, and that prospective diaries lead to the greatest consumption estimates. It is also clear that detailed questions about ‘actual’ rather than ‘usual’ consumption increase the amount of alcohol that is captured by social surveys.

Abbreviations:

24H = 24-hour recall, (BS) = beverage-specific, F= frequency, FFQ = quantity-frequency within food frequency questionnaire, GF = graduated-frequency, PD = prospective diary, Q = quantity, QF = quantity frequency, RR = recent recall, RD = retrospective diary, WDR = weekly drinking recall

p.w. = per week

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Table 2.2: Studies which have compared different measures of alcohol consumption

Study ID Year Country Sample size Population Comparison(s) Findings Notes

Poikolainen &

For QF, taking into account drinking pattern/context leads to higher estimates drinks p.w.. 8-14 day reference period = 7.7 drinks p.w.. 3-7 days, 15-30 days, one month and ‘usual’ = c.6 drinks p.w..

Qualitative examination supported the BS findings, but only weakly supported the differences between methods observed in the quantitative synthesis. WDR, 4% in GF, 3% in QF. Proportion of harmful drinkers:

1% in WDR, 4% in GF, 2% in QF.

Abbreviations:

24H = 24-hour recall, (BS) = beverage-specific, F= frequency, FFQ = quantity-frequency within food frequency questionnaire, GF = graduated-frequency, PD = prospective diary, Q = quantity, QF = quantity frequency, RR = recent recall, RD = retrospective diary, WDR = weekly drinking recall

p.w. = per week

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Study ID Year Country Sample size Population Comparison(s) Findings Notes

Dietary history and QF were highly correlated in both men although alcohol consumption was ‘under-estimated’ by 12% on the QF.

Heavier drinkers tended to under-estimate their drinking behaviours, and light drinkers tended to overestimate (see Section 2.6.7).

Small sample size

Stockwell et.

al. 2004 (90)

2001 Australia 21,674, aged 14+ General population

24H (BS), GF, and QF Mean difference of 1.1 drinks p.w. (95% CI 0.9-1.2) between GF and QF (not shown for recent recall).

The proportion of risky and high risk drinkers was 10.6%

using GF and 8.1% using QF (not shown for recent recall).

Consumption in litres of pure alcohol per person per year

Mean on PD (7 days) (13.9g) differed significantly from the means on QF (9.2g) and GF (9.8g), both P<0.01

Kendall’s Tau rank-order correlations between measures were all significant (P <0.01), and of modest magnitude.

Agreement was higher between QF and GF (s = 0.49) than between QF and PD (s = 0.45), than between GF and

Consumption increased the relative prevalence of heavy drinking (as >2 drinks a day for men, >1 for women) among all adults by 19-42% (depending on the method used to calculate a ‘binge’).

Among binge drinkers, the overall prevalence of heavy drinking increased by 53% points, resulting in half of women binge drinkers and half of binge drinkers aged over

Large sample size, but putative

Abbreviations:

24H = 24-hour recall, (BS) = beverage-specific, F= frequency, FFQ = quantity-frequency within food frequency questionnaire, GF = graduated-frequency, PD = prospective diary, Q = quantity, QF = quantity frequency, RR = recent recall, RD = retrospective diary, WDR = weekly drinking recall

p.w. = per week

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Study ID Year Country Sample size Population Comparison(s) Findings Notes

55 meeting the criteria for heavy drinking.

Stockwell et.

al. 2008 (38)

2004 Australia 24,109, aged 12+ General population

GF, QF, and 24H 24H gave the highest estimate, 7.53 litres pure alcohol per year (95% CI 7.19-7.86), 80.7% of alcohol sales. The GF estimate was 6.45 litres (95% CI 6.31-6.59); 69.2% of sales, and QF was 6.03 litres (95% CI 5.88-6.18); 64.4%

sales.

Boniface &

Fuller 2012 (1)

2011 England 4,969 General

population

QF, RR of heaviest day in the last week, and PD (7 day), (all BS).

Drinking frequency was similar between QF and PD.

Mean alcohol consumption among drinkers on the heaviest day in the RR was 7.7 units for men and 5.1 units for women, compared with 8.4 units and 5.9 units respectively in the PD.

Mean alcohol consumption p.w. was 17.4 units for men and 9.5 units for women in the QF, and 20.3 units and 12.5 units respectively in the PD.

This could also be due to mode effects: see Section 2.6.4.

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