The use of mixed methods models and designs in the human sciences: Problems and prospects

The article explores some of the emerging issues in the newly developing area of Mixed Methods (MM) research. Two of these issues concern the possibility of whether MM can provide for both "diverse" and "severe" testing. Based on a model of Placeholder Effects and utilizing an example of current empirical research, it is concluded that certain varieties of MM are potentially more robust than others in fulfilling the diverse and severe criteria. It is also argued that MM must concern itself with formulating "procedural rules" which guide the researcher in choosing and applying appropriate strategies for specific research problems.