This book aims to guide researchers who are engaged in social science and built environment research through the process of testing the reliability and validity of their research outputs following the application of different methods of data collection.The book presents case studies that emphasize reliability and validity in different examples of qualitative, quantitative and mixed method data sets, as well as covering action research and grounded theory. The reader is guided through case studies that demonstrate: An understanding of the reliability and validity approaches from social science and built environment perspectives in alignment with the relevant research philosophies, approaches and data collection strategies Real research projects that have been conducted by expert researchers on topics such as Lean, BIM, Housing and Sustainability to answer specific or evolving questions in relation to the reliability and validity of research A simple and easy method that students at Masters and PhD levels can relate to in order to adopt a sound reliability and validity approach to their research This book is the essential guide for researchers at undergraduate and postgraduate level who need to understand how to validate the quality of the empirical tests they conduct using different techniques. The book will also be a great asset to supervisors from different backgrounds who need a refresher on this key aspect of the research cycle.