And fair enough.
Fortunately, we have some evidence ready at hand. Byrnes et al, 2012, Drug and Alcohol Review. They use Australian household surveys from 2001, 2004 and 2007 to see how changes in alcohol prices affect the number of reported days of no, low, moderate, and high alcohol consumption; they find that while price increases do reduce consumption, they tend to reduce the number of days of low consumption while not changing the number of days of moderate and high alcohol consumption. This would be consistent with binge drinkers dropping the occasional beer or wine with dinner to save up for the big nights out. If policy is more worried about binge drinking than about light drinking, this might matter.
It's also mildly amusing that an Otago healthists complains about policy being based on surveys. I wonder what Connor would make of her Otago colleagues' call for banning smoking outside of bars on the basis of a survey of thirteen youths recruited in part via Facebook; the youths reported in focus groups that they'd be less likely to smoke if they couldn't smoke outside of bars. Maybe that one's ok because it's published in a journal rather than being a Masters Thesis.
Connor also notes that heavy drinkers tend to purchase cheaper alcohol relative to moderate drinkers.
“It has been established that hazardous drinkers spend less per unit of alcohol than others, and drinkers compensate for price increases by shifting to cheaper drinks. In the United States, the heaviest 10% of drinkers spend approximately $0.78 per drink compared with $4.75 per drink for the lightest 50% of drinkers.”This only is a relevant comparison if the heaviest drinkers and lightest drinkers are drawn from the same parts of the income distribution. Suppose for sake of argument that heavier drinkers are more likely to be drawn from poorer parts of the income distribution and lighter drinkers from higher income parts of the distribution. If that's the case, we would want to compare the price paid by heavy and light drinkers correcting for any differences in income. If people with demographic characteristics similar to the heaviest 10% of drinkers but who are light drinkers spend $1 per drink (just a guess here), then minimum prices pushing above that hit both heavy drinkers and light drinkers of modest income. I know that consumption benefits from alcohol count for zero in the healthist world, but they ought to matter for policy.
At least they're not today claiming that a 10% increase in minimum prices reduce consumption by 16%...