The differential effect of focus on form and focus on forms on the development of grammatical competence among IranianEFL high school students

Abstract The purpose of this study was to investigate the differential effect of two types of grammar instruction, focus on form (FonF) and focus on forms (FonFs), on the learning of grammatical features (do, does, and did). Three intact classes involving 45 male adolescent EFL learners in Iran, Tehran, were assigned into three groups. The study employed a pre-test, posttest, and delayed posttest design to measure the effectiveness of each treatment. The comparison groups received either FonFs or FonF instruction over three sessions. Moreover, the control group was taught using translation tasks. Results suggested that FonFs and FonF had differentiated effects on learners’ grammar knowledge. Although both forms of instruction showed positive gains in grammar knowledge from pretest to posttest, FonF produced more positive outcomes for students on grammar measure; however, these gains were not retained in the delayed posttest.