Two experimental batteries, each of three different types of writing tests, were given on three successive days in May 1950. One was given to all seniors at Phillips Exeter Academy; the other, to all seniors at the Choate School. Scores were compared to their Scholastic Aptitude Test (SAT) verbal scores (SAT-V) and the College Board English Test. The student's English teachers gave estimates of their writing ability. This became a criterion against which all measures were correlated. Written portions of the experimental tests were scored by four veteran College Board readers. There were 142 seniors at Exeter and 93 at Choate for whom comparisons are available. Correlations with ratings are given. They are compared with Edith Huddleston's 1947 validity study. Multiple correlations are given of SAT-V and each other test with ratings. Rank order of correlations of each measure with all others is given. The validity of the written correction exercises is discussed, as is reliability of the written correction exercises. The free essay received the second highest correlation with ratings. Correlations of objective corrective exercises are given. Verbal vs. reading items as predictors of writing ability are discussed. The SAT verbal score was the best single writing ability measure. The total score of the March 1950, College Board English Test stood up well in comparisons with the new experimental batteries. (SGK).