Although this is an unsettled area of law, it might depend on the test. Many widely used psychological tests ask questions that invade the test-taker's privacy. And the jury is still out as to whether these tests have any ability to predict whether a particular employee will lie, steal, manage poorly, or cause other workplace problems. Because of these limitations, it's a good idea to talk to a lawyer before imposing a testing requirement.

For more information, see Testing Employees.

You may not fire a worker because of his or her religious or political beliefs. Federal and state laws protect workers from this type of discrimination. However, if a worker brings those beliefs into the workplace by, for example, attempting to convert other workers or publicizing political beliefs during work time, you may put a stop to this.

For more information, see Monitoring Employees' Off-Duty Conduct.

Generally yes, depending on your policies. If you have a policy of email privacy (for example, if you tell your employees that their email will be confidential or will not be read by the company), then you should abide by that policy. Also, if you allow employees to designate certain messages as confidential or private, you probably shouldn't read the messages so designated. Otherwise, however, you have the right to monitor employee email, as long as you have a legitimate business purpose for doing so.

For more information, see Monitoring Employee Communications.

Yes, with a few limitations. You are legally allowed to monitor employee conversations with customers for quality control. Federal law allows you to do so without warning or announcement, although some states require you to inform the parties to the call in some way that you are listening. However, you may not monitor personal calls. You must stop monitoring once you realize that a particular call is personal.

For more information, see Monitoring Employee Communications.

This is usually a bad idea. Generally, you can perform a workplace search in order to serve important, work-related interests -- as long as you don't unduly intrude on your workers' privacy rights. Random searches are less likely to pass legal muster than a search of a particular employee whom you reasonably suspect of theft. And even if you have a reasonable suspicion, you must not search too invasively: Although searching an employee's bag might be reasonable under some circumstances, searching the employee's body crosses the line.

For more information, see Workplace Searches.