Focusing specifically on scientific research in criminal justice, the 4th Edition of this text introduces students to qualitative, quantitative, and mixed methods research in a uniquely applied, relevant manner easily understood by future criminal justice professionals. Divided into four sections (introduction to research in criminal justice; sampling methods; statistics; and common errors in presenting and interpreting research findings and technology), the chapters are easy to read, accessible, and chock-full of real-world criminal justice examples and data. There are also helpful pedagogical resources such as chapter learning objectives, examples, and key terms along with an excerpt of the Code of Ethics from the Academy of Criminal Justice Sciences found at the end of the book. This edition has been updated throughout to include descriptions of new practices and approaches, such as mixed methods data collection and analysis, and technological applications in data collection and analysis. In addition, some chapters have been combined to make room for new information such as an expanded discussion of qualitative research methods.