The last time you applied for a job, the hiring authority probably ran a background check on you, whether or not you were made aware of it. Most background investigations probe into an applicant's academic, professional and criminal histories. But every bit of information about your past isn't open for inspection. The law limits the type and volume of information that an employer may access. For example, employers can find out if you graduated from college, but they don't have the right to know your grade average. Employers can find out if you worked at a certain company, but they don't have a right to know about personal disputes you may have had there. Regarding criminal history, an employer may be found negligent for hiring someone who's been convicted of a violent crime and who later attacks or kills a co­worker. Employers may be charged with invasion of privacy if they don't properly advise job candidates that they may be investigated. It's a good idea for employers to have job applicants sign a consent form before conducting a background check. Additionally, only human resources personnel, a supervisor or an investigation agency should perform the background check. For information about other legal restrictions on employee screening, consult a labor and employment law professional in your area.