In Mixed Methods Research: Exploring the Interactive Continuum, the second edition of Qualitative-Quantitative Research Methodology, authors Carolyn S. Ridenour and Isadore Newman reject the artificial dichotomy between qualitative and quantitative research strategies in the social and behavioral sciences and argue that the two approaches are neither mutually exclusive nor interchangeable; rather, the actual relationship between the two paradigms is one of isolated events on a continuum of scientific inquiry.

In their original model for research--the "interactive continuum"--Ridenour and Newman emphasize four major points: that the research question dictates the selection of research methods; that consistency between question and design can lead to a method of critiquing research studies in journals; that the interactive continuum model is built around the place of theory; and that the assurance of validity of research is central to all studies. With this edition, the authors incorporate the concept of research purpose into their analysis.

To contextualize their new argument and to propose strategies for enhancement, Ridenour and Newman review the historical and contemporary debates around research frameworks and define the nature of scientific validity. Establishing five criteria that render a study "scientific," they propose ways to strengthen validity in research design. They argue that by employing multiple methods, researchers may enhance the quality of their research outcomes. By integrating the quantitative research standards of internal and external validity and the qualitative research standards of trustworthiness, Ridenour and Newman suggest a principle for mixed methods research.

Ridenour and Newman apply this theoretical concept to a systematic analysis of four published research studies, with special emphasis on the consistency among research purpose, question, and design.

Ridenour and Newman have completely rewritten their conclusions in light of their evolving analyses. They incorporate their most recent ideas into the qualitative-quantitative continuum and emphasize the "model of consistency" as key for research to meet the standard of "scientific."

This book occupies a vital place at the junction of methodological theory and scientific practice and makes connections between the traditionally separate realms of quantitative and qualitative research.

Carolyn S. Ridenour is a professor of educational leadership at the University of Dayton. She has published in numerous journals and has coauthored book chapters on the topics of mixed methods research, gender issues in schools, cultural diversity, the challenges of online education, and the impact of market-based policies on school reform in urban areas.

Isadore Newman, a licensed psychologist, is a professor emeritus at the University Of Akron College Of Education. He has coauthored many articles, written nine books and monographs, and served on many editorial boards. He is the editor of Multiple Linear Regression Viewpoints, Midwestern Educational Researcher, and the Ohio Journal of Science.