The midpoint formula provides a more accurate measure of percentage changes in quantities, like price and demand, by calculating the change relative to the average of the initial and final values. For example, if the price of a good increases from $10 to $12, the percentage change is calculated as (12 – 10) / [(12 + 10) / 2] * 100 = 18.18%. This differs from the standard percentage change formula which would yield 20%.
This approach is particularly useful in economics as it yields consistent results regardless of the direction of the change. Calculating the percentage change from $12 to $10 using the midpoint method produces the same 18.18% decrease, unlike the standard formula. This symmetry is essential for analyzing supply and demand elasticities, ensuring that the calculated elasticity between two price points remains consistent irrespective of whether the price rises or falls. The method is also preferred for its accuracy, especially over larger percentage changes, where the simple percentage change calculation can be misleading.
