These issues are discussed with clarity and passion in Action Research: Living Theory (A Jack Whitehead and Jean McNiff, 2006). Whitehead and McNiff put the case that Action Research is valid research technique, alongside those of the social and physical sciences. They claim action research as a rigorous and valid approach for a PHD thesis. What I found most useful was the explanation that Action Research was not trying to emulate social or physical science research methods, but do something different and more personal, with the researcher more involved with their subject.
After reading this book I feel I understand Action Research better. I can see its role in educational development and as an approach for scholarly discourse.
However, I am still not convinced this is equal to conventional scientific research techniques. It is useful for a practitioner sets down an educational technique they tried, to document their progress and as an aid to other. But that is not sufficient to base a theory of education on, or to make recommendations for widespread educational practice, or the investment of large amounts of education funding. Before deciding on a theory, practice or program I would want to see research which involved many educators and students and which applied statistical analysis techniques with tests to see the results were not due to chance, or wishful thinking.
Whitehead, J., & McNiff, J. (2006). Action research: Living theory: Sage Publications Limited.Worthington, T. (2000). Re-engineering the ACS Journal:
Notes for the launch of the Journal of Research and Practice in IT, 17 April 2000, Sydney. from http://www.tomw.net.au/2000/jrpitw.html