Early in the 2000s, a countrywide health services research initiative was launched under the acrony
m of Atlas VPM: Atlas of Variations in Medical Practice in the Spanish National Health Syste
m. This initiative ai
med at describing syste
matic and unwarranted variations in
medical practice at geographic level-building upon the se
minal experience of the Dart
mouth Atlas of Health Care.
The paper aims at explaining the Spanish Atlas experience, built upon the pioneer Dartmouth inspiration. A few selected examples will be used along the following sections to illustrate the outlined conceptual framework, the different factors that may affect variation, and some methodological challenges.