This is an unedited Right of Reply. I will also not comment. You may see that John has misconceptions about our commenters – which isn’t unusual. If you’re going to complain about it, then you’ll end up proving his point. I suggest you stick to the topic at hand and make me proud. Thanks.
You raised some questions today in your blog about my project which the Marsden Fund will support from 2015-17. Let me try to answer them. Please note that I am directly e-mailing you because I don’t comment on blogs. Some commentators on blogs seem impervious to evidence, so my commenting would probably be a waste of time. When I produce evidence that might be of interest to a blogger I do sometimes send it to them directly (e.g. on rising public sector wage premiums to David Farrar and on school zone effects to Eric Crampton) so I am not opposed to blogs per se but I do prefer to limit my engagement with them. Also note, that while I am an empirical economist and so will support conclusions based on what the evidence indicates, politically I would be broadly considered as right-of-center (not that this should be relevant) and am well aware of the limits to state action and the importance of individual responsibility.
a) what is already known in NZ and why is the study necessary?
A series of studies by Wellington School of Medicine researchers along with economists from Otago and NZIER used two types of data from Stats NZ: the Household Economic Survey (HES) and Food Price Index (FPI) data. They modeled the effect of prices on the shares of the household budget allocated to a number of food and beverage groups, with “energy drinks” as one group and “carbonated soft drinks” as another. Their model examined how households altered their budget shares for each item as prices changed. Based on their results, they concluded that “a 10% tax on carbonated soft drinks could lead to a 13% decrease in population purchases of these products”. The reduced purchases were assumed to all be in terms of quantities purchased, and this evidence, along with similar overseas studies has been influential with the NZMA etc in recommending a 20% tax on fizzy drinks as one way to combat rising obesity. Read more »