Indiana Code Title 6. Taxation § 6-1.1-31-3

(1) data compiled by the federal government;

(2) data compiled by this state and its taxing authorities;

(3) data compiled and studies made by a state college or university;

(4) generally accepted practices of appraisers, including generally accepted property assessment valuation and mass appraisal principles and practices;

(5) generally accepted indices of construction costs;

(6) for assessment dates after February 28, 2001, generally accepted indices of income accruing from real property;

(7) sales data compiled for generally comparable properties;  and

(8) any other information which is available to the department of local government finance.