Quasi-experimental Design - Essay Example

The quasi-experimental design looks like an experimental design but lacks arbitrary assignment. They are referred to as quasi-experimental because they give the experimental a queasy feeling. With respect to interior rationality, they often appear inferior to randomized experiments. There are two types of quasi-experimental designs. One of them is the non-equivalent group design which involves a pretest and posttest for a treated and comparison group and is the simplest form. It is indistinguishable from the analysis of covariance design except the groups are not created through random assignment (Finkelman).

According to Finkelman Non-experimental research design is the plan and structure of research to provide a credible answer to a research question. It describes the current existing characteristics like achievement, attitude, and relationships. There are four types of non-experimental designs which include; a descriptive design which describes phenomena, relationship design which describe the relationship between two or more variables, causal-comparative which uses correlational models to investigate possible causes and effect relationship and the last design survey which represents a data collection method that is very useful in descriptive and correlational studies because of its generalizable, efficient and versatile nature (Finkelman).

Small N design is generally used in phenomenological, behavior modification, psychophysics, and neuropsychological research and it is among the earliest designs used in psychology (Finkelman). Small N involves experimental manipulation and provides for better control of extraneous variables. Small N design is also limited because external validity may be lower if subjects do not resemble the population. The baseline conditions may also be difficult to recreate outside the laboratory. Single-subject designs also known as single-case designs are research designs that use the results from single participation or subjects to establish the existence of cause-and-effect relationships.

Finkelman state that experimental designs have meaningful roles and are often the best because of resource constraints and ethical considerations. Both non-experimental and quasi-experimental are valuable sources of scientific information and knowledge. These designs are the easiest ways to study diseases that develop slowly or are relatively rare. Understanding statistics with respect to statistics is also important because it is essential in engaging in a systematic review of previous research done by psychologists (Finkelman).