(1) If the school district uses a severe discrepancy model, it will use the OSPI's published discrepancy tables for the purpose of determining a severe discrepancy between intellectual ability and academic achievement.

(2) The tables are developed on the basis of a regressed standard score discrepancy method that includes:

(a) The reliability coefficient of the intellectual ability test;

(b) The reliability coefficient of the academic achievement test; and

(c) An appropriate correlation between the intellectual ability and the academic achievement tests.

(3) The regressed standard score discrepancy method is applied at a criterion level of 1.55.