How do you know someone is a "great developer" if you can't, in tangible terms, say exactly what a "great developer" is?
This is even more of an issue when recruiting because recruiting is an assessment process to determine if someone meets some requirement. But just like software testing, if you can't quantify the requirement, then you can't quantify a test to determine if someone meets that requirement, and therefore the interview/assessment process is simply voodoo recruiting.
Voodoo recruiting is when you have the appearance of scientific process in recruiting. - a process, - a set of questions that appear good, - a coding test that seems technical enough that it must be telling you something meaningful about the candidate, - the opinions of many people on the candidate. But in fact all of this is voodoo because you still can't directly define the requirement and thus you never known if you ever found what you are looking for, which is not actually known.
The final decision in recruiting a "great developer", as always, comes down to some subjective opinion based on a range of criteria that can't be proven to have had any meaning in the first place.