Sequential exploratory design

Mulford and Robinson (2) used a sequential exploratory design to develop the Chemistry Concepts Inventory, (CCI), a survey of alternative conceptions for use in first-semester general chemistry. The design of the study is illustrated in Figure 2. 

Figure 2. The sequential exploratory design strategy (Creswell, d W. Research Design, Qualitative, Quantitative, and Mixed Methods Approaches 2nd ed. p. 213, copyright 2003 by Sage Publications, Inc. Reprinted by Permission of Sage Publications, Inc.).

The sequential exploratory design is well aligned with survey development. As Morse (6) stated it allows researchers to explore the distribution of particular phenomena across a population. It can also be used to generalize the findings of a qualitative study to a broader population by the development of a quantitative instrument that is grounded in the data. 

Mulford, D. R. Robinson, W. R. An Inventory for Alternate Conceptions among First-Semester General Chemistry Students, J. Chem. Ed 2002, 79, 739-744 (2). This article nicely documents the development of this inventory using a sequential exploratory research design. 

There is an alternative, rather more economical, composite design for 3 factors, based on a (resolution III) 2 design, a star design and centre points (5). It allows determination of the second-order model, but its properties are inferior to those of the full design. In particular it is not rotatable. This design may be useful as it allows sequential experimentation with a small total number of experiments (about 12-14). Thus the exploratory 2 design may be completed by the axial points. It has been used for the optimization of a solid dispersion (6). 

An exploratory sequential design informed the research methodology, where the first method (qualitative) informed the second method (quantitative) (Greene 2007). This method is well suited for exploring a phenomenon (Plano Clark and Creswell 2008) and is useful when the researchers need to develop an instrument because one is not available (Creswell 2009). 

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