[irundebian]

Software engineering may not be an engineering discipline but in theory you could set up empirically studies/experiments to test certain hypotheses of software development practices. In theory you could also review or evaluate design against certain criteria and derive what's better to fulfill certain goals.

[flixic]

And yet, when the subject boils down to people and culture, testing is slow, complicated and unrewarding. Results need a lot of variable elimination and are rarely used for practical decision making. This applies to most “people” subjects.

Testing nature is much easier, and thus establishing norms in these subjects is easier.

[tadzik_]

Absolutely. And I think there were actually studies on the effectiveness of TDD, and I seem to recall them confirming it.