A study to check on the efficacy of the teaching methods used in "Language Basics Plus," a basal elementary language arts program published by Harper and Row, involved a pretest, treatment, and mastery test procedure used with more then 3,000 elementary students. Results of the prepublication learner verification study indicated that the instructional methodology used in the text and teachers' editions was effective. Areas for revision and improvement to be made in the published version were identified. Teacher reaction was positive, and it was noted that the materials were appropriate at the indicated grade levels. (Tabular data are included, and a list of objectives taught in the trial lessons is appended.) (AEA)