1. 'Tell me about yourself.' Open-ended questions can elicit more information than specific ones. When answering that kind of question, the elements that a candidate chooses to emphasize can be illuminating. Listen for statements that clue you in to the intangibles most important to success in the position.
2. 'Can you work overtime? Weekends? Night shifts?' Some interviewers draw conclusions about the willingness of a candidate (especially women with children) to work long hours or extra hours. Directly question all candidates about their willingness and ability to work nonstandard hours.
3. 'Do you feel comfortable lifting
50 pounds several times a day?' Don't assume that certain candidates aren't able (or willing) to do hard manual duties or work with hazardous materials. You can even test the applicant's ability to perform the task. Just don't make assumptions.
4. 'Do you have any physical limitations that would keep you from performing the job's essential functions?' You're entitled to know, but caveats exist. First, you must clearly define a job's essential functions. Second, you must ask this question of all applicants.
You can also ask what type of accommodation applicants would require. But you can only ask this if the person has an obvious disability or the applicant volunteers that he or she has a disability.
5. 'In what way has your education prepared you for this job?' For many positions, a high school (or college) diploma doesn't qualify as a bona fide occupational qualification. Instead of asking about a piece of paper, ask about specific skills that the applicant needs for success.