Question

Types, advantages and dis advantages of quasi experimental research design

Answer 1

Advantages:

• Quasi-experimental research may be more feasible because it often does not have the time and logistical constraints associated with many true experimental designs.
• True experimental designs are sometimes impractical or impossible because the research can only effectively be carried out in natural settings. Experimental research can create artificial situations that do not always represent real-life situations. This is largely due to fact that all other variables are tightly controlled which may not create a fully realistic situation.  For this reason, external validity is increased quasi-experimental research.
• Reactions of test subjects are more likely to be genuine because it not an artificial research environment.
• It can be very useful in identifying general trends from the results, especially in social science disciplines.
• It reduces the difficulty and ethical concerns that may surround the pre-selection and random assignment of test subjects. For example, if examining the effects of cigarette smoking by pregnant women on the fetus, it would be unethical to randomly assign pregnant women to groups.
• Matching procedures may be used to help create a reasonable control group, making generalization more feasible. For example, if one group of migraine suffers received a new treatment and a second group did not receive the treatment, the difference in the pain levels may be attributed to the treatment if the control group is an appropriate comparison group.
• The results generated can often be used to reinforce the findings of case studies by conducting research that may lend itself to statistical analysis.

Disadvantages:

• The lack of random assignment into test groups leads to non-equivalent test groups which can limit the generalizability of the results to a larger population. Beside of the lack of randomization and the reduced internal validity, conclusions about causality are less definitive in quasi-experimental designs.
• Statistical analyses may not be meaningful due to the lack of randomization and the threats to internal validity.
• Pre-existing factors and other influences are not taken into account because variables are less controlled in quasi-experimental research. For example, when examining the impact of smoking by pregnant mothers, there may be other factors such as diet, education, overall health, and access to health care in general that may be playing a role in the outcome.  If other variables are not controlled, the researcher can be assured that the treatment was the sole factor causing the outcome.
• Human error also plays a key role in the validity of any project as discussed in previous modules.
• The research must adhere to ethical standards in order to be valid. These will be discussed in the next module of this series.

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Answer 2

Types of quasi-experimental research design are nonequivalent groups design, regression discontinuity, and natural experiments.

Explanation:

• The main disadvantage of quasi-experimental designs is that they cannot remove the possibility of confounding bias, which can make it difficult to draw causal inferences. This disadvantage is frequently used to dismiss quasi-experimental data.

• When compared to individual randomised controlled trials (RCTs) or cluster randomised trials, the most significant benefit of quasi-experimental investigations is that they are less expensive and needless resources.

• The absence of random assignment into test groups results in non-equivalent test groups, limiting the generalizability of the results to a broader population.