ABSTRACT: This paper makes an argument for testing all four language skills (listening, reading, writing, and speaking), as opposed to testing more selectively. It is the broader trait of communicative competence, not specific individual skills, that is critical in most academic and workplace settings and of most interest to users of tests like the TOEFL and TOEIC tests. It is important, however, to test for each of these four skills individually because each is a critical aspect of communicative competence. When test scores are used to make consequential decisions, the use of several sources of information yields better decisions than does a more selective use of information. Moreover, assessment is fairer to test takers if they are allowed to demonstrate their skills in multiple ways — with different tests, different methods, and different question formats. Comprehensive testing also encourages broader and more generalizable teaching and learning of language skills by test takers. All of the reasons given here are consistent with the trend toward more comprehensive, integrated testing of language skills as seen in many prominent language testing programs. This paper is part of the Research Foundation for TOEIC: A Compendium of Studies, published by ETS in 2010.