Although the search for a reliable, quantitative measure of the maturity of written composition antedates LaBrant's (1933) subordination index, it was not until Hunt's (1965) identification of the T-unit that quantitative measures of sentence and clause length factors could be demonstrated to be valid, reliable indices of maturity. Following Hunt's exploration of the T-unit, several researchers attempted to design measures embodying linguistic features beyond clause and sentence length factors which indicate the maturity of written composition. Such scales include Botel and Granowsky's (1972) formula for measuring complexity: A directional effort, Endicott's (1973) proposed scale for and Golub and Kidder's (1974) syntactic density score.