I thought I’d a share a slide I came across while studying for a final in health economics (Econ 157). This shows the effects government intervention can have on a given market. In this case we are analyzing the effect of taxation (as opposed to subsidization) on the shift in the demand and supply curves. Who pays for the tax depends on the elasticities of both supply and demand, where less elasticity results in paying a higher share of the tax. For example, the burden of a cigarette tax would fall more upon the smoker versus the supplier, as they are likely addicted and have a relatively inelastic demand curve. This might also be true for a gasoline tax, which many economists support.