The first problem with scientific evaluation, suggests Kushner, is that programs typically have multiple and contested goals; hence, no single set of goals can serve as a fixed referent for comparison. An early finding of our evaluation was that the SCR program had numerous goals (e.g., politicians were oriented to performance and efficiency targets, doctors saw the main goal as improving clinical quality in out-of-hours care, and civil liberties lobbyists perceived the program an attempt by the state to encroach on individual privacy) [21].
http://plosmedicine.org/article/info:doi/10.1371/journal.pmed.1000360#article1.body1.sec2.p4

Surely 'multiple....goals' do form a set of goals that can be each evaluated?

In the SCR example given, the performance, efficiency and safety goals mentioned seem valid ones that can be evaluated against.

Each goal may be contested - in that all stakeholders don't agree that it was an intended goal of the project, though surely 1. an evaluation can proceed on the basis of assumed goals i.e. 'if a goal of the SCR was ..... then it did ....'. 2. at some point someone must have written down intended outcomes for the project? How else could the project have been funded or even explained to anyone?

Having multiple (maybe conflicting) goals does mean that there is not a simple success/fail that can be applied to the project, but presumably it is not unique in this respect?