Median price ratio
# Median price ratio

The median price ratio (MPR) is the ratio given by dividing the median local unit price of a medication by the median international reference unit price, usually from the International Medical Products Price $Guide.^{:220}$ This measure was created in 2003 by the Health Action International (HAI) and World Health Organization (WHO) as a standard measure to facilitate national and international comparisons of drug $prices.^{:41}$

In the WHO/HAI systematic methodology, the same provider of international reference unit price "must be used for all medicines surveyed – global, regional and supplementary", to ensure a consistent basis for $comparison.^{:38}$

Some authors criticized the MPR, as it can be skewed by the international reference price. For example, a 10% MPR for a $10 reference price yields an absolute price variation of $1, whereas for a $200 reference price the variation would be $20. To solve this issue, the WHO/HAI recommend to check the international reference price when very high or low MPR variations are $observed.^{:41}$

The MPR has been used in several studies investigating the availability and variation of medication prices, and the effects of various medication pricing policies.

The HAI maintains a regularly updated database of worldwide MPR $surveys.^{:7}$

