Re: Judging the applicants
You can judge them on process, outcomes or volume, if asking about quality of work.
A proxy for volume is experience - I've done the job for 5 years. For outcomes the example of the orchestra is obvious; some IT jobs could esaily be managed too. Process - again that's easily standardised at lower levels (eg "describe how you'd fix this problem") but more challenging when asking for jobs higher in responsibility/variability.
And none of this gets around the "do they fit in here" problem. Which is more marked in less diverse workplaces, as you don't fit in if you're very different and nobody else is...
Icon: I leave as an exercise for the reader how to shortlist pirate recruits.