a study of quality and quantity of nominal groups in the vision and interchange series

Materials evaluation plays an important role in language teaching as it helps practitioners to develop an awareness of the coverage and quality of the existing materials and as such, guides most instruction and revision decisions. therefore, we sought to evaluate three english vision textbooks exclusively written for iranian secondary high school students through a comparison to the identical interchange book series, the fifth edition. following a model of nominal groups outlined here, the evaluation targeted the quantity and quality of the groups appearing in the two series as they are assumed to be an important part of authentic language. for the quantitative part, the results indicated a significantly higher use of nominal groups in the interchange series. similarly, in the qualitative analyses, we found higher quality nominal groups appearing in the interchange books. the findings revealed inadequate inclusion of nominal groups’ potentially useful structures in the vision textbooks, supposed to help teachers to raise an awareness so as to come up with appropriate instructional policies, and the textbook developers to consider the findings when any revision is due.