Portmaneau, what I said was to explain why arearadar essentially kept repeating the question - certain or probable.
I agree with your definition, the various facts, and lack of facts, all add up to create the picture.
For an air traffic controller however they need to be 100%. In the absence of SSR they will ask for a position check or request an ident turn etc,
Even that has on occasion been less than 100% where another aircraft has inadvertently performed a similar manoeuvre and been mis-identified.