Doing a good job with intel involves many things i.e. collecting information, properly evaluating the info (not only if it is valid, but what it actually means), bringing the info to to those who can best act on it, selecting the most appropriate response, executing that response, analysing the results of the response to determine whether additional action is required. Plenty of opportunities for failure, and many as well for partial success. Secrecy does indeed play an important role in what we are allowed to know to protect sources, methods, and the thinking patterens behind all this (if you figure out how the other guy thinks, you can spoof him or attempt to direct his actions).
Hard to figure out most of the time whether the job we do is good, good enough, or as good as can be expected.