If it's worth quoting, it's also worth sharing (and crediting): Herman, R., & Renz, D. (1998). Nonprofit Organizational Effectiveness: Contrasts Between Especially Effective and Less Effective Organizations. Nonprofit Management and Leadership, 9(1), 23-38.

But to your point, if I am getting it, organizational effectiveness is a construct and we would do well to come up with more sophisticated and nuanced ways to measure it?

I like the practice of older or more established (but fragile) NPOs coming together to create newer ones with specific purposes to help them carry out their missions more effectively. Something to consider for funding, perhaps? Is that the start of a "system"?