Measurement assuredly lends more objectivity and reliability to textbook evaluation and selection and enables it to provide a lens into the actual effect of how teachers use an ELT textbook on the academic literacy of learners. This paper reports a trial project for computation of cohesion metrics of ESP texts for Iranian students of computer sciences. The project first shedded light on some inadequacy of the text selection rubrics within the paradigm of text-driven materials development problematizing the subjective, intuitive, impressionistic criteria for the selection of the core text. Then it raised two questions. They asked what enables achievement of the multi-dimensional mental representation of texts on the part of the target learners and how it is accomplished. Third, it introduced a utility application called Coh-Metrix that was developed to compute instantly and automatically cohesion ad readability indices. Forth, it put to test some existing ESP text for students of computer sciences for cohesion indices in order to make a tentative comparison with some grade level 6 science text against cohesion metrics. Lastly and never to be least, it concluded that explicit cohesive characteristics of texts enable the achievement of multidimensional mental representation of the text by selection and assignment of a core text cohesive enough using some objective metrics. Iranian EFL teachers and materials developers can, by implication, employ objective measures as they are evaluating and selecting core texts.