Every employer wants employees who have a positive attitude and will stay on the job so they often follow the hire-for-attitude, train-for-skills approach to staffing. To identify candidates with the right fit, many employers administer employment tests — including ones they've designed themselves. Unfortunately, the design-it-yourself path is laden with legal landmines.

One human resources manager recently shared this story with me:

For several months, I have been reviewing different pre-employment assessments to use in our organization. During this week's managers meeting, one of the managers announced he was creating his own test and the rest of management bought into the idea. His arguments were convincing. First, he outlined how it would save money if they didn't have to purchase a system. Second, he felt that he and the other managers knew what it took for an individual to succeed in their organization.

This situation prompted her to email me, "Is it legal for us to use a manager's do-it-yourself pre-employment test?"

The short answer is yes. It's perfectly legal…as long as it can be proven to be job-relevant and fair. That means a homegrown ...