Doriki (道 力, Dōriki?) Which means "Strength") Basically is the Level of one's physical strength, and thus has a proportion to Rokushiki's skills. In the Viz Manga, it is called the Power Level. This can be measured by Fukuro with "te-awase" (手 合 わ, "te-awase"?), Which means "match", he did it with other CP9 members after their first reunion after five years. An armed soldier generally has an average of about 10 Doriki, and according to Spandam, the Level Doriki 500 is enough to be called a superhuman. The terms Doriki and Te-awase were first introduced in Chapter 379 and Episode 266.
According to Jabra, the game is only for measuring one's physical fitness and does not take into account the strength given by Devil Fruit, though some Devil Fruits (especially Zoans) have side effects that directly increase one's physical strength. There is no more detail given about how Doriki can be confused.
It seems that Rob Lucci, Kaku and Jabra are three members of the CP9 (incidentally, they are the three humans who ate the Zoan type in CP9), even though the power of Devil Fruits is not taken into account, where their Doriki are all drastically higher than others. It also seems that from the start, Jabra had the highest Doriki of all CP9, he also commented that he had never heard of the Doriki number as high as 4,000 before Rob Lucci. Doriki Nero was never given, but Lucci stated that he was not worthy of being a member of the CP9, only mastering four Rokushiki techniques.
Source : WIKIA ONE PIECE