As I understand it, there were at least three hypotheses under consideration:
a) No members (or a negligibly small fraction) of the ethnic group in question will make any attempt at sabotage.
b) There will be attempts at sabotage by members of the ethnic group in question, but without any particular organization or coordination.
c) There is a well-disciplined covert organization which is capable of making strategic decisions about when and where to commit acts of sabotage.
The prior for A was very low, and any attempt by the Japanese government to communicate with saboteurs in the States could be considered evidence against it. Lack of sabotage is evidence for C over B.
As I understand it, there were at least three hypotheses under consideration: a) No members (or a negligibly small fraction) of the ethnic group in question will make any attempt at sabotage. b) There will be attempts at sabotage by members of the ethnic group in question, but without any particular organization or coordination. c) There is a well-disciplined covert organization which is capable of making strategic decisions about when and where to commit acts of sabotage.
The prior for A was very low, and any attempt by the Japanese government to communicate with saboteurs in the States could be considered evidence against it. Lack of sabotage is evidence for C over B.