Octane testing varies nationally. In the US we use the average of a specified lab (research) test and a test in a specific motor (R+M)/2, as defined by the American Society for Testing and materials, ASTM.

There are other methods and other crietria on other countries, as livvie mentioned. They may or may not use or coexist with ASTM.

Similarly, engine/motor power is measured differently in different markets- net, brake, etc etc.