Academic references to outcomes theory: Duignan (2009a; 2008b; 2008d)*
You can think of these as like a set of playing cards that can be played when arguing in support of a program or organization's effectiveness.
If some cards are strong then you don't have to worry so much about playing your other cards.
Six of the seven outcomes system building-blocks can be seen as six types of evidence that can be offered that a program works (building-blocks one to six).
However, if some of your major cards are weak, you can compensate for this by playing a good mix of cards from all of the possible six measurement-related building-blocks.
* This particular reference can be cited to refer to the material on this page.