Please respond with a paragraph to the following post, add citations and references.

The four most commonly used designs for research studies are descriptive, correlational, quasi-experimental, and experimental (Grove, Gray, & Burns, 2015, p. 23). Descriptive and correlational designs are referred to as non-experimental designs. This is due to the focus being on examining variables as they naturally occur in environments and not the application of a treatment by the researcher.

In experimental design researchers use random assignments and they change an independent variable around a controlled variable. A true experimental design must have randomization, manipulation of a variable and a control group when examining the direct cause or predicted relationships between variables. In a quasi-experimental study design one of these aspects is missing (Sousa, Driessnack, & Mendes, 2007).

A non-experimental research design focuses on examining variables as they would naturally occur such as survey, case studies, correlation studies, comparative studies and descriptive studies (Grove et al., 2015, p. 212). Non-experimental designs have no random assignments, no control groups and no manipulation of variables, the research design is observation only (Sousa, Driessnack & Menders, 2007). There are many ways in which nonexperimental research can be the case.

1. The research question or hypothesis is about a single variable rather than a statistical relationship between two variables.
2. The research question is about a noncausal statistical relationship between variables.
3. The research question is about a causal relationship, but the independent variable cannot be manipulated, or participants cannot be randomly assigned to conditions or orders of conditions.
4. The research question can be broad and exploratory, or it can be about what it is like to have a particular experience.

(Price, Jhangiani, & Chiang, 2015, Chapter 7)

References

Grove, S., Gray, J., & Burns, N. (2015). Understanding nursing research (6th ed.). St. Louise, MO: Elsevier Saunders.

Price, P. C., Jhangiani, R. S., & Chiang, I. A. (2015). Research methods in psychology (2nd Canadian ed.). [Press Books]. Retrieved from https://opentextbc.ca/researchmethods/

Sousa, V. D., Driessnack, M., & Mendes, I. A. (2007, June). An overview of research designs relevant to nursing: Part 1: Quantitative research designs. Revista Latino-Americana de Enfermagem, 15(3). https://doi.org/10.1590/S0104-11692007000300022