Professor Dame Rachel Griffith

Getting a healthy start: the effectiveness of targeted benefits for improving dietary choices

Following a recent judgment, the UK Supreme Court confirmed that Scottish Government legislation for a minimum unit price for alcohol is lawful. The Scottish Government plans to introduce the measure on 1 May 2018. Meanwhile, the Welsh National Assembly is considering introducing a minimum unit price for alcohol. In this briefing note, we provide evidence on the likely impact of this type of reform.

CEPR Discussion Paper DP12499

We study optimal corrective taxation in the alcohol market. Consumption generates negative externalities that are non-linear in the total amount of alcohol consumed. If tastes for products are heterogeneous and correlated with marginal externalities, then varying tax rates on different products can lead to welfare gains.

Soda taxes aim to reduce excessive sugar consumption. Their effectiveness depends on whether they target individuals for whom the harm of consumption is largest. We estimate demand and account for supply-side equilibrium pass-through. We exploit longitudinal data to estimate individual preferences, which allows exible heterogeneity that we relate to a wide array of individual characteristics. We show that soda taxes are effective at targeting young consumers but not individuals with high total dietary sugar; they impose the highest monetary cost on poorer individuals, but are unlikely to be strongly regressive if we account for averted future costs from over consumption.

Corrective taxes have been implemented in a number of countries with the aim of addressing growing concern about the rise in obesity- and diet-related diseases. The rationale is that food consumption imposes costs on the consumer in the future that they do not fully take into account at the point of consumption (‘internalities’). Corrective taxes have the potential to improve welfare by reducing suboptimally high consumption. We review the literature on the size of these internalities and on the optimal corrective tax, which depends on the patterns of internalities, the price responsiveness of consumers, and on redistributive aims.

Paper forthcoming in Quantitative Economics.

We present a method to estimate preferences in the presence of unobserved choice set heterogeneity.

The government has recently consulted on the structure of alcohol taxes. This consultation focuses on two issues: (i) the introduction of a new still cider and perry band that would increase the tax on products below 7.5% ABV, and (ii) the introduction of a new still wine band that would reduce the tax on products between 5.5% and 8.5% ABV. Here we summarise the main points from our response to the consultation.

There have been calls for restrictions on junk food advertising to tackle rising rates of obesity around the world. This column examines the likely effect of a ban on potato crisp advertising. Results suggest that the total quantity of crisps sold would fall by around 15% in the presence of a ban, or by 10% if firms respond with price cuts. The welfare benefits from this would depend on whether current advertising is persuasive, informative or complementary.

Governments have long used taxation to correct for the socially costly overconsumption of alcohol, but as the external cost of overconsumption varies across drinkers, a single tax rate is not optimal. This column argues that variation in preferences for different products and in price responsiveness across heavy and light drinkers provides scope to improve welfare by varying tax rates across alcohol products. The proposed framework is well suited to addressing other sources of external costs, such as obesity.