Due to the nature of office cleaning jobs and the fact that cleaners often are left to work unsupervised around confidential information, expensive equipment and sometimes money, most cleaning companies conduct background checks. Reputable cleaning companies are also insured and bonded to protect themselves and the client against damages.
In short, background checks ensure that prospective employees are who they say they are. The extensiveness of a background check depends on the employer and the kind of work involved, but most companies check to verify work history, education, history of criminal offences and outstanding warrants. The background check also includes the calling of references. Sometimes background checks also include a credit check, civil history and a review of driving history (mostly only for delivery-type jobs). Background checks are most common in careers that require a great amount of trust (such as cleaning, driving, accounting and working with children), as well as high-level, high-paying jobs.
If one is hiring a company, it's a good idea to ask specifically what its particular background checks on its employees involve, as it can vary greatly. While conducting background checks certainly helps ensure that the workforce is free of convicted criminals, it does not mean that there is zero risk of criminal activity from an employee.