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Design Decisions in Research

4. The Design and Planning Phase

Research Design

The research design is the overall plan for conducting a study that will optimize the ability to achieve the study purpose and obtain accurate results.

Quantitative designs require control, precise measurement, and numerical data to describe, predict, or determine the cause and effect of relationships. Different designs are used depending on the research problem and purpose of the study.

Nonexperimental designs typically describe a phenomenon, compare characteristics of two or more groups, or examine relationships among variables. Methodological research to develop or refine questionnaires often uses nonexperimental designs. In contrast, quasi-experimental or experimental designs are used to determine the effect of an intervention and if rigorous in design, provide strong evidence to guide clinical practice (Melnyk & Fineout-Overhold, 2005).

Table 5

Common Quantitative Research Designs

  Definition Major characteristics
Non-experimental Descriptive – describe and/or compare characteristics or prevalence
Correlational – to examine relationships among variables
Methodological – to develop the reliability and validity of instruments .
Collection of data without any intervention
Quasi-Experimental To examine the effects of an intervention. Manipulation (intervention) Missing Characteristic: Control (control or comparison group) AND/OR Randomization (assignment to intervention or control group randomly)
Experimental To examine the effects of an intervention. Manipulation (intervention) Control (control or comparison group) Randomization (assignment to intervention or control group randomly)

Table previously published in: Whittemore, R. & Melkus, G. (2008). Designing a research study. The Diabetes Educator, 34, 201-216.

Melnyk, B. M., & Fineout-Overhold, E. (2003). Evidence-based practice in nursing and healthcare: A guide to best practice. Philadelphia: Lippincott Williams & Wilkins.