IB Economics SL Internal Assessment Example

Two relevant diagrams are included and both are accurately labelled.

The diagrams clearly show the relationship between private and social costs and the resulting welfare loss.

The tax diagram correctly shows how an indirect tax can shift the market toward the socially efficient outcome.

There is a small inconsistency in how one supply curve is named in the text versus the diagram.

The explanation could be slightly tighter in stating that the market price reflects private costs rather than social costs.

The welfare analysis would be even stronger if the student explicitly discussed what happens when the tax is not equal to the external cost.

Economic terminology is used consistently and appropriately across the commentary.

Relevant terms such as demerit goods, negative externalities, allocative efficiency, deadweight loss, indirect tax, and price elasticity of demand are integrated into the argument.

The terminology supports the analysis rather than appearing as isolated vocabulary.

There are occasional imprecise statements, especially around the revenue effects of the tax.

Some wording blurs the distinction between a regressive tax and the broader welfare impact on low-income households.

A few references could be more precise in distinguishing proposed policy from implemented policy.