A comprehensive review was conducted of writing research literature and writing test program activities in a number of testing programs. The review was limited to writing assessments used for admission in higher education. Programs reviewed included ACT, Inc.'s ACT™ program, the California State Universities and Colleges (CSUC) testing program, the College Board's SAT® program, the Graduate Management Admissions Test® (GMAT®) program, the Graduate Record Examinations ® (GRE®) test program, the Law School Admission Test® (LSAT®) program, the Medical College Admission Test® (MCAT®) program, and the Test of English as a Foreign Language™ (TOEFL®) testing program. Particular attention was given in the review to writing constructs, fairness and group differences, test reliability, and predictive validity. A number of recommendations are made for research on writing assessment. Tables Summarizing Previous Studies of Mean Differences, Reliability, and Validity are provided in the appendix.