Then the AI is twice as likely to pick the focus with the factor of 20. So if there are only two focuses available, one has a factor of 10 and the other has a factor of 20. When the AI needs to pick a focus within its focus tree, it considers all possibilities and then picks a random number between 0 and all factors added together. it is used as part of defining national focuses and government positions. The ai_will_do value is used as a subobject that determines the likelihood the AI will pick something for the country.