The OSA uses public accounting firms, consulting firms, and other independent contractors to help fulfill its audit and other responsibilities. Contracted services may be broad in scope, such as performing an entire audit, evaluation, or study.  Alternatively, contracted services may be more limited in scope, such as providing specialized expertise (e.g., medical file review, actuarial services, appraisal reviews, complex statistical analyses) as part of an in-house audit, evaluation, or study.