I understand that the P-ATC gives the per unit economic profit
Why is this the case? Why wouldn't we take price minus the marginal cost?
I understand that the P-ATC gives the per unit economic profit
Why is this the case? Why wouldn't we take price minus the marginal cost?
Price minus marginal cost gives you marginal profit.
\begin{align*} \text{Total profit}&=\text{Revenue}-\text{Total cost}\\ \frac{\text{Total profit}}{\text{Quantity}}&=\frac{\text{Revenue}-\text{Total cost}}{{\text{Quantity}}}\\ &=\frac{\text{Revenue}}{{\text{Quantity}}} - \frac{\text{Total cost}}{{\text{Quantity}}}\\\\ \text{Per-unit profit}&=\text{Price}-\text{Average total cost} \end{align*}