Non-experimental Research Designs


Besides experimental research designs (which rely more on random and laboratory controls), there are other types of research and designs which are more descriptive and may not necessarily rely on random and laboratory controls.  These include but not limited to Case study research design, Content Analysis research design , Causal Comparative (Ex Post Facto) research design, Ethnographical Research Design, Grounded Theory Research Design, Phenomenological and Design, Philosophical Research Design and Survey research design.


Case Research Design

According to Creswell (2003), a case study is an in depth exploration of a program, an event, an activity, a process, or one or more individuals (p. 15). The case study can be either a single case or a case bound by time and place (Creswell, 1998). Leedy and Ormrod (2001) provide several examples from different disciplines such as a medical research studying a rare illness (event) or political science research on a presidential campaign (activity). According to Leedy and Ormrod, case studies attempt to learn “more about a little known or poorly understood situation” (p.149). The data collection for a case study should be extensive and drawn from multiple sources such as direct or participant observations, interviews, archival records or documents, physical artifacts, and audiovisual materials. The researcher must spend time on-site interacting with the people studied. The report should include lessons learned or patterns found that connect with theories. One of the major limitations of case study research design is that the results can not be generalized. Case studies can form proposition upon which further studies can be conducted.


Content Analysis Research Design

Leedy and Ormrod (2001) define this method as “a detailed and systematic examination of the contents of a particular body of materials for the purpose of identifying patterns, themes, or biases” (p. 155). Content analysis reviews forms of human communication including books, newspapers, and films as well as other forms in order to identify patterns, themes, or biases. The method is designed to identify specific characteristics from the content in the human communications. The researcher explores verbal, visual, behavioral patterns, themes, or biases in order to make inferences.


The procedural process for the content analysis study is designed to achieve the highest objective analysis possible and involves identifying the body of material to be studied and defining the characteristics or qualities to be examined (Leedy & Ormrod, 2001). The research report may have the following sections: the description of the materials studied, the characteristics studied, a description of the methodology, the analysis based on the objectives, and conclusions about the patterns, themes, or biases found in the analyzed content or data collected.


Causal Comparative (Ex Post Facto) Research Design

Causal comparative studies are also called ex post facto because the investigator has no control over the exogenous variable since whatever happened occurred before the researcher arrived therefore there is no certainty that the two groups were exactly equal before the difference occurred (Dehejia & Wahba, 2002). In causal comparative design, two groups that differ are selected and comparison is done. Inferential analysis such as t-test (for two groups) and Analysis of Variance (comparison of means for more than two groups) or Chi Square (for frequency data) are used. Researchers often infer cause and effect relationships based on such studies.

Correlation Research Design

Schmidt (1989) notes that a correlation study is used when you want to take a look at variables and see if they have any relationship. Scientists use terms like positive correlation, negative correlation and no correlation to describe the relationship among variables in a correlation study. In scientific research, correlation does not necessarily imply causation, in that two variables may be associated without having a causal relationship.  According to Stanovich (2007), correlation studies, appropriately used, are important to science in terms of the following:

  • Scientific hypotheses are stated in terms of correlation or lack of correlation,
  • Although a correlational study cannot definitely prove a causal hypothesis, it may rule one out.

The importance of correlation studies lie in the fact that once correlation is known, it can be used to make predictions. Therefore, the stronger the relationship between and among variables, the more accurate the prediction is. Thus, correlation studies can form a strong foundation for more rigorous experimental studies.


Descriptive Research Designs

Descriptive research designs are applied in various qualitative studies which use observation and interview methods such as case studies, ethnography among others. These designs help to provide answers to the questions of who, what, when, where, and how associated with a particular research problem. These designs can never however answer the question of ‘why’. Descriptive research designs are used to obtain information concerning the current status of the phenomena and to describe “what exists” with respect to variables or conditions in a situation (Anastas, 1999).

Descriptive research designs typically are characterized by the following:

  • Use of observation of the subject under study in its natural setting or environment,
  • Serves as a pre-cursor to more quantitatively research designs,
  • Can form the basis for developing a more focused study,
  • Can yield rich data that lead to important recommendations.
  • Collection of a large amount of data for detailed analysis.

The limitations of descriptive research designs lie in the following:

  • The results can not be used to discover a definitive answer or to disprove a hypothesis.
  • The results cannot be generalized since the since the designs often utilize observational methods which are purely qualitative (USC, 2013).


Ethnographic Research Design

According to Creswell (2003), in ‘ethnographies, the researcher studies an intact cultural group in a natural setting over a prolonged period of time by collecting, primarily, observational data’ (p. 14). Ethnography studies an entire group that shares a common culture (Leedy & Ormrod, 2001). The focus is on everyday behaviors to identify norms, beliefs, social structures, and other factors. Ethnography studies usually try to understand the changes in the group’s culture over time. As a result, findings may be limited to generalization in other topics or theories.


In the ethnographic research design, the researcher must become immersed in the daily lives of the participants in order to observe their behavior, then interpret the culture or social group and systems (Creswell, 1998). The initial step in the ethnography process is to gain access to a site. Second, the researcher must establish rapport with the participants and build trust. Third, the researcher starts using the big net approach by intermingling with everyone in order to identify the key informants in the culture (Leedy & Ormrod, 2001). The design makes use of the participant’s observations and interviews of key informants. If the interviews are lengthy, the researcher gathers documentation by using audiotapes or videotapes media. In this design, the researcher must give the justification for the study, the description of the group and method of study, the findings to the research questions and conclusions about group’s shared culture that developed over time.


Read more … types of research designs



Anastas, J.W. (1999). Research Design for Social Work and the Human Services. Chapter 5, Flexible Methods: Descriptive Research. New York: Columbia University Press.

Creswell, J. W. (1998). Qualitative inquiry and research design: Choosing among five traditions. Thousand Oaks, CA: SAGE Publications.

Dehejia, R., & Wahba, S. (2002). Propensity Score-Matching Methods For Nonexperimental Causal Studies. The Review of Economics and Statistics84 (1), 151-161.

Leedy, P., & Ormrod, J. (2001). Practical research: Planning and design (7th ed.). Upper Saddle River, NJ: Merrill Prentice Hall, Thousand Oaks.

Stanovich, K. (2007).  How to Think Straight About Psychology.  Boston, MA: Pearson.

University of Southern Carlifornia (USC) (2013). Types of Research Designs. Retrieved from