This review critiques the use of Lev Vygotsky's concept of the zone of proximal development (ZPD) in quantitative research that focuses on the role communication plays in learning. A study that makes claims in terms of the ZPD should include a pretest, a problem-solving activity, and a posttest. Without these minimal elements, researchers are not working specifically with the ZPD. This review explores research on the ZPD and evaluates how closely each study approximates the necessary elements. It was found that only 3 of the 15 studies analyzed include all of the elements necessary to make claims in relation to the ZPD. This review does not aim to nullify some studies and applaud others; rather, it aims to highlight work that uses the ZPD as a means of interpreting experimental results. What some researchers do not realize is that Vygotsky had some very specific guidelines in mind when he introduced the idea of ZPD. Contains 24 references. (Author/TB)