ABSTRACT
Scientific research consists of a vast number of contributions throughout history. Each contribution to the broader fabric of science represents a blend of personalities and perspectives over time. Additionally, many individuals and movements are responsible for the principles and practices of what have now come to be known as research design. Two factors stand out as particularly important in the evolution of the design and analysis of all types of research: better methods for controlling the performance of variables of interest and improved mathematical modelling of behavioral phenomena. Yet, large-group research designs, designs for which most developments and issues have emanated, actually originated in the study of the individual.
