When a job has physical requirements that not all potential employees can meet, some companies use a pre-hire human performance evaluation to screen out applicants who can't perform essential job tasks, such as lifting heavy objects. Tests of this type must be designed carefully to avoid violating laws against discrimination in employment.

Haste Makes Waste

It's both expensive and inefficient to hire an employee only to find out after he's already started that he is physically incapable of performing the job. For instance, if the job requires employees to be able to lift boxes weighing up to 50 pounds and load them on a pallet, then employees who cannot lift 50 pounds repeatedly cannot perform well in the position. Rather than taking a gamble on whether the employee can perform the job, some business owners prefer to screen all new hires before making a final job offer.

One Size Does Not Fit All

Human performance evaluations usually measure the ability to push, pull, carry or pick up objects used in the job. A consultant from a company specializing in human performance evaluations can usually customize a test for a specific job based on the physical requirements of that job. For instance, if a job requires repetitive motion, but doesn't require any heavy lifting, the consultant will design a human performance evaluation based on the motions used in that specific job.

Validity and Reliability

Any business owner considering the use of pre-employment testing needs to consider the possibility of being taken to court over the test. To be legal for use as a pre-employment screening tool, a test must be both valid and reliable. A valid test is one that accurately measures a person's ability to perform the job in question. For instance, if a job only requires employees to lift up to 20 pounds, but the test requires applicants to lift up to 50 pounds, then the test does not measure whether an applicant could perform the job because some applicants who could do the job would flunk the test. A reliable test produces consistent results. An applicant should receive approximately the same score no matter how many times he takes the test.

Discrimination Factor

Employers must also be sure to avoid committing illegal discrimination in their use of pre-employment screening. For instance, if a job requires only infrequent heavy lifting, it might be a violation of the Americans with Disabilities Act to screen for heavy lifting ability as a condition of employment. The test should screen only the essential skills needed to perform the job on a daily basis, not all skills that might ever be called for. A test can also be considered discriminatory if members of a particular minority group tend to be screened out by it disproportionately.