A medical practice often consists of several different techniques whose cumulative rates of use constitute the overall rate of use. The proportion of use rates for these techniques is not always consistent across geographical areas, which may reflect differences in therapeutic choices, especially if overall rates of use are similar.
One example is bariatric surgery, which, as a whole, shows a fairly clear geographical split between the North and South of the country (see figure below).
If we take the analysis further, and consider the use of the main bariatric surgery techniques (‘bypass’, ‘sleeve’ and ‘banding’), we gain new information, showing very different choices of technique in the various regions of Belgium (see figure below). We can then compare these relative rates of choice of technique with the procedures used in other countries (the right-hand column - ‘Global data’): this shows that, despite the overall high rates, the South of the country chooses to use techniques more in line with international practice.
 Angrisani, L., Santonicola, A., Iovino, P., Vitiello, A., Zundel, N., Buchwald, H., & Scopinaro, N. (2017,Sept). Bariatric Surgery and Endoluminal Procedures: IFSO Worldwide Survey 2014. Obesity Surgery, 27(9), pp. 2279–2289.