Quasi-Experimental Designs - Essay Example

Application of Quasi Experimental Designs: A Case Wise Study Research designs are not only to be studied in theory; but they do have an important role to play in deciding the way data collected for a study will be interpreted. The research design helps us identify the strengths and weaknesses of the study and the extent to which the results of a particular study are applicable in said situations. In the succeeding examples; the methodology helps us understand how to interpret the results of the studies.

Study 1 demonstrates that women perform more poorly, on average, than men perform on the mathematics section of the Scholastic Aptitude Test (SAT).  Wainer, H., Steinberg, L. S., (1992). Sex Differences in Performance on the Mathematics Section of the Scholastic Aptitude Test: A Bidirectional Validity Study. Harvard Educational Review. Vol. 62(3), pp. 323-337. Reason for choice: Studies like these are part of classic literature on abilities and on psychological testing. The study also provides support for the urban legend that boys (males) are better at mathematics as compared to girls (females).

This study also provides a perfect example for understanding quasi-experimental designs, since the selection of subjects in each group can be randomised perfectly; but the actual manipulation of the Independent variable is impossible. Variables: The independent variable for this study is the sex of the participant, and the dependent variable is the score obtained by the participant on the mathematics section of the SAT. Alternate research design: The same study results would be more valuable if the effect of study background was removed.

This can be done by using a measuring the extent to which the subject has studied mathematics or mathematics dependent subjects in the two years before giving the exam; and then removing the effect of this variable from the data by using an Analysis of Co-Variance. The study would still have a quasi-experimental design; but the results would be more robust as the effect of previous learning would have been equalised (Kerlinger, 1986). If the study results still showed a significant difference, this would mean that sex does play a role in mathematical ability regardless of previous learning.

If the difference is not significant, then it would seem that previous learning plays a stronger role then sex of the individual (Guilford, 1978). Study 2 demonstrates that lower-socioeconomic-status students benefit more over time from an academic tutoring program than do higher socioeconomic-status students.  Greenwood, C. R., Delquadri, J. C., Hall, R. V., (1989). Longitudinal effects of classwide peer tutoring. Journal of Educational Psychology. Vol. 81(3). Pp. 371-383. Reasons for choice: This study compares two groups again, but the attempt here is to study changes as affected over a period of time.

Longitudinal studies are important in Psychology, as they help in understanding trends, given the background variables (McBurney, 2002). Variables: The independent variable is the socio-economic status of the participant, and the dependent variable is the extent to which the student benefits from academic tutoring. Alternate research design: The same results may be obtained by using a cross-sectional design. Students from the two backgrounds who have been receiving academic tutoring for varying periods of time may be selected for the study, and tested for difference from their pre-tutoring scores on exams.

Such a study will help us understand the minimum and the optimal amounts of tutoring that are needed to help a student score well. Using a cross – sectional method helps in saving time and controls for the effect of the study itself (Snodgrass, et. al., 1985). From the above examples; it can be seem that the design of the research study plays an important part in understanding the strengths, weaknesses and applications of the study. The quasi experimental designs help in studying areas and topics that the not open to study using experimental designs.

Nevertheless, they provide valuable information about the topics being studied and when they are used effectively, are almost as valuable as the data collected using experimental studies. References: Guilford, J. P., Fruchter, B., (1978). Fundamental Statistics in Psychology and Education. 6ed. New York: McGraw-Hill Book Company.  Kerlinger, F.N. (1986).  Foundations of behavioral research. Orlando, FL: Holt, Rinehart and Winston, Inc. McBurney, H. H. (2002). Research Methods (5th Ed). Pacific Grove, CA: Brooks Cole.

Snodgrass, J.G, Levy-Berger, G. and Haydon M. (1985). Human experimental psychology. Oxford university press. New York. USA. Print.