Just yesterday (or so it seems), job interviews were simple: you interviewed the most promising applicants and hired the best ones. Today, nothing about employment is simple — and that includes job interviews.

Being a fair-minded, careful employer is no longer enough to keep you out of legal hot water. A complex web of hiring rules can easily ensnare a business owner or manager. Fortunately, you can avoid most hiring problems by following a few basic guidelines:

• Start by writing a job description for each position. That will help make the hiring process more objective.

  Make sure your job descriptions don’t discriminate against applicants. As you know, you can’t discriminate on the basis of an applicant’s race, skin color, sex, religion, national origin, physical disability — or age, if the applicant is at least 40 years old.

  List the qualifications you’re seeking, such as necessary skills, education, experience and licenses. Also set out the essential job functions — a task made tougher by the Americans with Disabilities Act (ADA). This law strives to give people with disabilities a fair crack at job openings.

  Legally, you should list only the job’s core duties. Otherwise, someone may get turned down just because he or she can’t perform a marginal job requirement. For example, suppose your job description for a file clerk includes answering the phone but, in actual practice, the job consists of filing and retrieving order forms. Other employees usually answer the phone.

  Someone whose hearing is impaired may have trouble handling phone calls but be perfectly able to take care of the order forms. Phone answering isn’t an essential in the job, so — to comply with the ADA — you shouldn’t list it as such in the job description.

  Besides preparing a job description before you start interviewing, it pays to write down a set of questions focusing on the job duties and the applicant’s skills and experience. Some examples:

  “Tell me about your experience in running a mailroom.”

  “How much experience did you have in making cold calls on your last job?”

  “Explain how you typically go about organizing your workday.”

  “Have any of your jobs required strong leadership skills?”

  By writing down the questions and sticking to the same format at all interviews for the position, you reduce the risk that a rejected applicant will later claim unequal treatment.

• Tell the applicant about the job — the duties, hours, pay range, benefits and career opportunities. Then get into the applicant’s work history and relevant experience.

  Think twice before venturing beyond these fairly narrow topics. You can quickly find yourself in legal quicksand.

  The Rules of Etiquette once dictated that you avoid discussing sex, religion or politics in a social setting. Although that standard has been relaxed, it still applies to job interviews — and you must also avoid focusing on an applicant’s age, ethnicity, birthplace or marital and family status.

  Stick to job requirements and company policies. Suppose you’re concerned an applicant may have young kids and will spend too much time talking with them on the phone. You can’t ask: “Do you have children?” or “Who watches the kids when you’re at work.”

  But you can say to the applicant: “We don’t allow personal phone calls during work hours. Do you have a problem with that?” The applicant can let you know if a problem exists. Just be sure you apply your phone policy equally to all employees.

  Similarly, you have little right to control what an employee will do on his or her own time — so, generally speaking, you can’t refuse to hire smokers. You can, however, prohibit smoking at your place of business.

  This means you shouldn’t inquire whether the applicant smokes. It’s OK, however, to state that you have a non-smoking workplace.

  Now for the delicate area of how to deal with an applicant who may have a disability — a topic governed by the ADA.

• Ask about the applicant’s ability to perform job tasks and about any needed accommodation. Focus on the ability of the applicant to do the job — not on a disability.

  An employer can’t discriminate against people with disabilities if they can handle the job — and the employer must provide reasonable accommodations to help them do so. A worker with very poor eyesight, for example, may need a computer screen that magnifies the letters.

  Consider this example. Arthur, who has only one arm, applies for a job that requires driving. To avoid legal problems, avoid asking Arthur if or how this disability would affect his driving.

  Instead, ask: “Do you have a valid driver’s license?” “Can you drive on frequent long distance trips, with or without an accommodation?”

  Then say: “At least 80 percent of the time of this sales job must be spent on the road covering a three-state territory. What is your selling experience? What is your accident record?” These are permissible questions.

  You can describe or demonstrate the specific job tasks. Then ask if the applicant can perform these tasks with or without an accommodation. You can also ask an applicant to describe how he or she will perform specific job functions — if you require this of everyone applying for a job in this category.

  While the rules are stringent, there’s a simple and legal way to get needed information about a person’s disability and whether it will prevent the person from doing the job.

  Under the ADA, you can make a conditional job offer — an offer conditioned on the applicant taking a medical exam. You must, however, require this for all candidates who receive conditional job offers in the same job category.

  If you withdraw a conditional job offer for medical reasons, be prepared to show your reasons were job related and consistent with business necessity, or the person was excluded to avoid a direct threat to health and safety.

  You’ll also need to show that you couldn’t make a reasonable accommodation to the person’s disability.

• Finally, in any job interview — whether or not the person has a disability — watch what you say about job security. Here’s why. You may want to fire the applicant someday without having to prove that you had a good reason to do so.

Traditionally, the law has followed the employment-at-will doctrine. This allows you to fire an employee for any reason or no reason at all — as long as you don’t do it for an illegal reason such as firing an older worker to make room for a younger person.

By being careless at a job interview, you may lose this right to fire. For example, if you promise job security and then fire the worker, the discharged worker may claim you didn’t have a just cause and that you violated an oral contract. Many a fired worker has sued on such a theory and won a big verdict.

Legal questions of general interest will be considered for future columns. Write “The Legal Advisor” in care of PM. See your own lawyer for specific legal advice.