Imagine you advertised an open position, and are now sitting down to review a stack of 100 resumes.
If the first ten resumes you read are terrible, you feel a sense of dread coming over you. Without realizing it, you lower the bar, so if the 11th resume is even close to being qualified, you breathe a sigh of relief and eagerly move them to the "Yes" pile.
But if the first ten resumes you read look well-qualified, you raise the bar. You become very selective about who makes it into the "Yes" pile. You invent new criteria to help you winnow the field.
In both cases, that 11th resume is not being judged strictly on its own merits, it's evaluated primarily by what came before it.
In the first case, all those unqualified resumes are corrosive to your selectivity. You get desperate and lower your standards. This happens with astonishing frequency in hiring.
In the second case, an abundance of apparently good choices leads to hyper-selectivity. You get picky on criteria unrelated to job performance just to save time interviewing. You become desperate to "weed out" some people that would have been perfectly fine otherwise. You rule out people without stopping to consider that you only have a resume and your assumptions ... but none of the facts. In my experience, the best candidate rarely has the best resume, so being hyper-selective in resume review always causes you to overlook potentially great people.
So how do you prevent yourself from arbitrarily raising or lowering your standards?
You have to notice what is not in front of you. That stack of 100 resumes may or may not be representative of the available pool of people for your job. And each resume may or may not be representative of the true talents of each person.
Ask yourself two questions:
Before you select candidates from the stack of 100 bad resumes, ask yourself, "Am I confident that this candidate pool represents the best people I could attract to this job?"
Before you rule out good people from the stack of great resumes, ask yourself, "Have I fairly considered everyone potentially qualified for the job, or have I ruled out people based on factors that may be irrelevant and assumptions that might be inaccurate?"
You may find that in both cases, you forged ahead, trying to "save time" in the interview sequence, instead of taking the necessary time to hire the best possible person for the job.