This report presents an overview of research related to the development of the "Wisconsin Tests of Testimony and Reasoning Assessment," a battery of seven tests for assessing student development in the mastery of relevant concepts and skills of verbal argument for grades 10-12. Provided are (1) a discussion of the rationale for and purposes of the tests, (2) a discussion of the development of the tests, and (3) a description of each test, reliability and item data, and a brief discussion of the significance of the data gathered by administering the fifth edition of the test battery to over 3,000 junior/senior high students in four Wisconsin school systems. Included is a discussion of the specific objectives of the tests: to measure the student's ability to evaluate testimony in terms of internal criteria, consistency with other testimony, and recency and proximity; to recognize and select warrants in arguments; to recognize statements which answer reservations in arguments; to select reservations in arguments; and to select claims in arguments. Thirty-one tables and two figures offer further information. (Author/LH)