Objectives. To assess the possibility of bias due to the limited target list
and geographic sampling of the World Health Organization (WHO)/Health Action International
(HAI) Medicine Prices and Availability survey used in more than 70 rapid sample surveys since
Methods. A survey was conducted in Peru in 2005 using an expanded sample of
medicine outlets, including remote areas. Comprehensive data were gathered on medicines
in three therapeutic classes to assess the adequacy of WHO/HAI’s target medicines list and the focus
on only two product versions. WHO/HAI median retail prices were compared with
average wholesale prices from global pharmaceutical sales data supplier IMS Health.
Results. No significant differences were found in overall availability or prices
of target list medicines by retail location. The comprehensive survey of angiotensin-converting
enzyme inhibitor, anti-diabetic, and anti-ulcer products revealed that some treatments not on the
target list were costlier for patients and more likely to be unavailable, particularly
in remote areas. WHO/HAI retail prices and IMS wholesale prices were strongly correlated for
higher priced products, and weakly correlated for lower priced products (which had higher
estimated retailer markups).
Conclusions. The WHO/HAI survey approach strikes an appropriate balance between modest research costs and optimal information for policy. Focusing on commonly
used medicines yields sufficient and valid results. Surveyors elsewhere should consider the
limits of the survey data as well as any local circumstances, such as scarcity, that may call
for extra field efforts.