The services required by this article which are not practically deliverable directly from the department may be subcontracted to professionally qualified private individuals, associations, agencies, corporations, partnerships or groups. The service provider shall be required to submit monthly activity reports as to any services rendered to the department of human services. The activity reports shall include project evaluation in relation to individual families being served as well as statistical data concerning families that are referred for services which are not served due to unavailability of resources. The costs of program evaluation are an allowable cost consideration in any service contract negotiated in accordance with this article. The department shall conduct a thorough investigation of the contractors utilized by the department pursuant to this article.