30 ILCS 5/3-5
The Auditor General shall conduct special studies of the obligation, receipt, expenditure and use of public funds of the State at the request of the chairman and minority party spokesman of the appropriations committee of the Senate or the House of Representatives or of any joint committee established by the General Assembly which has been given jurisdiction to review such public funds. The "minority spokesman" means that member designated as such by the minority leader of the Senate or House of Representatives, as the case may be.
Special studies may not be in the nature of post audits or investigations, but may consist of:
To the extent that manpower and funds are available to his office for that purpose, the Auditor General shall conduct special studies but shall afford them a lower priority than such post audits and investigations as are required or directed under this Act.
In connection with such special studies, the State Treasurer and the State Comptroller shall provide the Auditor General with such reports and data maintained by their offices as may be requested by the Auditor General and, at the request of the Auditor General, shall develop and provide such additional reports as are capable of being provided with data processing facilities ordinarily utilized by their offices. The costs of such additional reports shall be borne by the Treasurer or the Comptroller, as the case may be.
30 ILCS 5/3-5