You can bar a convicted applicant from employment only if the offense relates to responsibilities of the job position. The statement should also state that if hired the employee may leave the job at any time. Furthermore, photographs of the applicant cannot be required. Most of such questions may be answered once the individual is hired, since much of the information is needed for insurance and other filing applications. However, asking any of the prohibited questions either on the application or at the interview, and then denying employment, opens the employer to a potential discrimination suit which can be costly and very difficult to defend.
Background checks are important in the hiring process.
It is part of common sense due diligence. However, under current law it is difficult to get specific information which will help you make a hiring decision. You need the applicant's consent to conduct a credit check or to check references. Typically, references will only confirm that they know the applicant or that he or she was employed during a given period of time and in what capacity. It is obviously helpful if you can get the applicant to volunteer the information that you are seeking, without directly asking for it.