Sugar-Sweetened Beverages — Market Failure and Factors in Policy Choice

Question

From end-2021, pre-packaged sugar sweetened beverages (SSB) with a high sugar or saturated fat content will be required to display a nutrition label with grades ranging from A to D, with D being the unhealthiest. Retailers will also be banned from advertising D-grade drinks on all media platforms.

(a) Explain how the pursuit of self-interest by consumers leads to an inefficient outcome in the SSB market. [10]

(b) Discuss the factors that the government should consider when implementing policies to achieve a more efficient allocation of resources in the SSB market. [15]

Answer

Part (a) [10]

The pursuit of self-interest by consumers makes the SSB market fail on two counts: a negative consumption externality and imperfect information. Both lead to over-consumption relative to the socially optimal quantity.

Negative consumption externality. When consumers consume SSBs, third parties not party to the transaction bear external costs — for example, diet-related illness such as diabetes lowers the productivity of the labour force on which producers across the economy rely, and burdens public healthcare. Because a rational consumer considers only his private costs and benefits, these external costs are not priced in, so marginal social cost (MSC) exceeds marginal private cost (MPC). The consumer consumes at Qm, where MPC meets marginal private benefit (MPB), which exceeds the social optimum Qs, where MSC meets MSB. The over-consumption generates a deadweight welfare loss.

Imperfect information. The market also suffers from imperfect information through ignorance. Consumers may not perceive the true private cost of SSBs — unaware of the high sugar content and the illnesses that frequent consumption can cause. Their perceived MPC lies below their actual MPC. They consume at Qm where perceived MPC meets MPB, whereas the socially optimal Qs (absent externalities) occurs where actual MPC meets MPB. The result is again over-consumption and a deadweight welfare loss. Because the divergence here is between perceived and actual private cost rather than private and social cost, the inefficiency is illustrated through the relationship of those two marginal-cost schedules rather than a separate externality figure.

Part (b) [15]

The question turns on the factors a government weighs, not merely on listing policies. A rational government considers the benefits, costs, constraints, information, perspectives of other agents, and unintended consequences of a policy. The stand of this essay is that costs and benefits are the most important factor, with the candidate policies — a tax and a public-education campaign — used to illustrate how each factor bears on the choice.

Benefits and costs. The government first weighs the benefits of a policy against its costs. A tax equal to the marginal external cost at Qs shifts MPC up to MPC + tax, which meets MPB at the social optimum Qs, internalising the externality and eliminating the deadweight loss — the benefit. Against this stands the cost: a tax must be enforced, incurring administrative outlays, and the budget so spent cannot fund other welfare-improving policies, an opportunity cost. A public-education campaign — informing consumers of the true private cost of SSBs — yields the benefit of closing the gap between perceived and actual MPC, again removing the loss; its costs are the explicit outlays on educators, advertising and venues, and the implicit opportunity cost of the policies forgone. By the marginalist principle, the government proceeds with a policy only where its expected benefit exceeds its cost.

Constraints and perspectives. The government also weighs constraints — public education tends to require larger explicit outlays than a tax, so a tight budget may rule it out — and the perspectives of other agents. If a tax is set too high, the price of SSBs rises sharply and consumers’ material standard of living falls, which may dissuade the government from taxing heavily.

Judgement. Costs and benefits are the most important factor. By the marginalist principle, whatever the constraints or perspectives, a government will not implement a policy whose total cost exceeds its total benefit — so the cost–benefit test is logically prior. In the Singapore context this judgement is reinforced: as a developed economy with large reserves, Singapore rarely faces a binding budget constraint, so constraints weigh less heavily; and because close, untaxed substitutes such as water and unsweetened tea exist, a tax on SSBs need not greatly reduce consumers’ material standard of living, so the perspective of consumers is a less decisive consideration. Costs and benefits remain the governing factor.