Not specifically a “fail fast” blog post but Dave Kellog recently expressed his thoughts on the value or structuring/designing business initiatives to allow for drawing specific conclusions based on the results of the initiative.
He argues that the results of the initiative should clearly indicate whether it was a repeatable failure or a repeatable success.
He is describing one of the ways to maximize the utility of failure (and/or also success in this case) through critical thinking and considering the possibility of failure while still planning.
A “test” that yields inconclusive results due to the way it was structured (i.e. could have yielded conclusive results with an alternative formulation) should not be considered failing fast.