In a doomed attempt to save time, many hiring managers unwittingly make themselves both more desperate and more biased in their hiring decisions. When you prematurely narrow the number of candidates you are willing to interview, you set up the perfect storm for bias and desperation.  Here's why.

The Washington DC metropolitan area has a great job market. As I said in The Washington Business Journal,  job seekers have the upper hand again. Mid-career professionals often receive multiple job offers and can afford to be choosy. This means that candidates who do well in their first interview with you often withdraw from consideration before you've even had time to schedule their second interview.

So, if you have not started your first round interviews with a field of at least six highly qualified candidates, you will probably find yourself coming down to the wire with only one viable candidate. That makes your hiring decision both simple and dangerously flawed. When you only have one person, your choice is either a) hire, or b) don't hire. Really, the choice is a) continue doing two jobs, or b) get help from someone. So naturally most hiring managers a) decide to hire now, and b) live to regret it later.

A recent study suggests why you make better decisions by improving your frame of reference. Harvard Professor Iris Bohnet explains it this way:

"Our hunch is that the mechanism works something along the following lines: if you look at one pair of shoes, it's hard to evaluate the quality of those shoes. You will be much more likely to go with stereotypes or heuristics or rules of thumb about shoes. But if you have several pairs of shoes available, you're much more likely to be able to compare different attributes of the shoes."

The Harvard study showed promising results in removing gender bias from hiring and promotion decisions, but the frame of reference principle applies equally well to other aspects of hiring, such as evaluating the competencies and cultural fit of the candidate.

Don't set yourself up to make a bad decision. Do what it takes to assemble a robust slate of qualified candidates, you won't regret it.

For more perspective on how to set salaries and how to make job offers, see How to Make a Job Offer and Negotiate Salary for a New Hire,