Hiring people is rarely based on objective evidence and is, perhaps, the least-objective activity that organizations participate in.

When we see a candidate who meets a large number of our pre-existing conditions for employment (i.e., a candidate who has gone to a school our hiring manager likes; has worked at a couple of well-respected companies; or has written the right key words on his resume), we have already hired him in our minds.

Interviews are examples of how easy it is to abandon the tools of objectivity, the scientific method, logic, and the rules of evidence, for our gut or for chemistry.

While there is considerable evidence showing that testing candidates is far more likely to predict successful performance, we still rely almost exclusively on interviews. Though numerous researchers have pointed out the need to gather a variety of data about a candidate, we generally settle for an application form and an interview.

Why are we so resistant to testing and other more objective sources of data?

Perhaps it is because our expectations, preconceptions, and prior beliefs pretty much always influence our interpretation of new information. Experiments conducted over and over have shown that we see what we expect to see and conclude what we expect to conclude.

Tom Gilovich, a Cornell University psychologist, writes:

Information that is consistent with our pre-existing beliefs is often accepted at face value, whereas evidence that contradicts them is critically scrutinized and discounted.

I was recently helping a hiring manager evaluate his staff for promotion. We carefully determined success criteria and agreed that the candidates had to meet those criteria for consideration. In fact, we spent quite a bit of time validating the criteria and ensuring that others agreed with them. We then tested his entire staff using highly validated, widely accepted tests of ability and potential.

As you might expect, one of his favorite people did not do very well on any of the tests. He struggled with what to do and finally decided that his own judgment was more valuable than the tests and promoted her. Six months later she was not performing, was not happy, and he was now faced with the task of demoting her or letting her go.

This is just one example of some general truths. If we are presented with evidence from a test that a person we really like is not very good at whatever skill we are looking for, we say that he must have had a bad test day or we find some other excuse to downplay the tests results because we want to hire him.

On the other hand, if the person had not gone to the right schools and not worked at the right companies, or had displeased us in some way, we would be more likely to accept the test results as accurate.

There are countless examples of how we deceive ourselves in the process of interviewing and screening candidates. We ask leading questions to elicit the responses we want: You have made presentations to senior management, haven t you? We ask references the same kinds of leading questions.

It is not that we dont examine information critically. In fact, experiments have shown that we look at all the evidence quite carefully, but we subtly massage it to make it support our preconceived idea or wish.

If evidence seems negative of our desire, we find excuses for why the information is bad or we lower it in our priorities for making a decision. We do just the opposite for favorable information.

We also will find data to validate our choices later on. If a person is successful, we will tend to attribute that to our superior interviewing skills, but if they fail we will find other reasons. Managers and recruiters are expert at the art of scapegoating their poor hiring decisions. What is most interesting, is how often someone removed from the process predicts the end result well before it happens because they see things more clearly and do not suffer the same preconceptions.

The bottom line is that assumptions, beliefs, and interviews are very poor tools for selecting people for specific jobs. It is almost impossible to apply objectivity to the interview process or to rid ourselves of deeply held (and mostly unconscious) beliefs.

Here are three things you can do to make you more effective as a selector:

Become aware. While we cannot prevent our preconceptions from clouding our judgment, we can apply corrective measures. We can develop criteria for jobs that are based on competencies, not on beliefs that cannot be validated or objectively supported. We can apply the scientific method to the recruiting process, just as we do to most other processes. I highly recommend How We Know What Isnt So by Thomas Gilovich at Cornell, and Super Crunchers: Why Thinking-by-Numbers Is the New Way to Be Smart by Ian Ayres. They are eye-openers to how easily we are duped and misled by seemingly objective evidence and by our own human nature.

Learn that superficial, circumstantial evidence is probably misleading and often wrong. Every court of law has developed elaborate rules of evidence to ensure that they get as accurate and well-rounded view of a situation as possible. Even with all of those rules and procedures, many innocent people still get convicted. Finding objective criteria and evidence takes time and a willingness to seek it out.

Use objective tools such as validated tests and multi-rater feedback. By starting with one or two well-known tools, we can refine and hone them to our exact needs until they are excellent at predicting success. Proctor and Gamble has been doing this for more than two decades with remarkable success.

When it is essential that people learn rapidly and perform at superior levels, you need objective and repeatable ways to judge candidates. No scientist would rely on interviews, feelings, or opinions to judge a scientific experiment. Neither should we in judging a candidate.