Professional skills expected from science, technology, engineering and math (STEM) students are well-aligned with the broad learning outcomes defined by the Accreditation Board of Engineering and Technology (ABET). While acquisition of professional skills in our graduates is increasingly crucial due to global competition and intensifying pressures on companies, the absence of a robust assessment framework limits effectiveness of pedagogical efforts by faculty. Thus, there is a need for an assessment model, which can help assess students' professional skill development across multiple disciplines. In this paper, we introduce a web-based application, called Peer Evaluation and Assessment Resource (PEAR), to assist in assessing students' development in professional skills, and we illustrate how this tool can be used for teamwork assessment. PEAR intends to streamline the processes of peer evaluations. PEAR has been designed based on the theory of Model of Domain Learning (MDL), and thus can help explain the complex interactions among knowledge, interest level, and strategies with which knowledge is gained. We illustrate the workflow of PEAR and how MDL is integrated into the peer assessment process. We also discuss the advantages of the MDL-based assessment framework compared to a traditional assessment model.