CLASSIFYING NONEXPERIMENTAL RESEARCH
In the literature on experimental studies, there is agreement on the distinction between
true- and quasi-experiments
true experiments use random assignment of subjects to groups and random assignment
of groups to treatments.
Quasi-experiments use preexisting intact groups, which are
randomly assigned to treatment conditions.
Classification Based on Purpose
Descriptive nonexperimental research, in which the primary focus for the research is to describe some phenomenon or to document its characteristics
Predictive nonexperimental research, in which the primary focus for the research is to predict some variable of interest using information from other variables
Explanatory nonexperimental research, in which the primary focus for the research is to explain how some phenomenon works or why it operates
Classification Based on Time
Cross-sectional research, in which data are collected at one point in time, often in order to make comparisons across different types of respondents or participants
Prospective or longitudinal research, in which data are collected on multiple occasions starting with the present and going into the future for comparisons across time
Retrospective research, in which the researcher looks back in time using existing or available data to explain or explore an existing occurrence
Combining Classification Dimensions
The researcher may combine the other classifications giving as a result the following ones
Descriptive retrospective
Descriptive cross-sectional
Descriptive prospective
Predictive retrospective
Predictive prospective
Predictive cross-sectional
Explanatory retrospective
Explanatory cross-sectional
Explanatory prospective