In the study by Grantham et al. (2006), convenience or accidental sampling was used, and the most convenient people were selected as the study participants. Regardless of the convenience and frugality of this sampling method, it is necessary to consider its disadvantages, including the possible sample bias and the reduced representativeness of the population, for evaluating the appropriateness of this approach critically. The same method of convenience sampling was used in the second study by Maloney & Weiss (2008). Even though in the second study, the participants were selected from the original sample according to the definite criteria for inclusion or exclusion, the data was retrieved from only one clinical setting and, consequently, the principle of representativeness was understated, resulting in the increased risks of the sampling biases.
The bias introduced by the method of convenience non-probability sampling, which was used in the study by Grantham et al. (2006) for evaluating the effectiveness of the self-medication programs, can result in sampling bias and the lack of representativeness in the achieved results, which would not allow making any generalized conclusions (Polit & Beck, 2004, p. 291). Regarding the convenience sampling method used in the study by Maloney & Weiss (2008), it can be stated that due to the study design, the elements did not have equal chances for being selected and the participants of the study were not able to represent all the characteristics of the population. Though retrieving the data from an entire population is impossible, careful sampling is required for achieving unbiased estimates (Yoon & Horne 2004). In that regard, it can be stated that the sampling methods used in the research under consideration were predetermined with the convenience consideration and could contain certain biased estimates.
The eligibility criteria were not clearly defined in the two studies, and none of the approaches can be replicated. Taking into account that convenience sampling was used in these two types of research, it can be stated that the definition of the criteria was not detailed. Still, some of the criteria were disregarded, whereas some of the definitions were inappropriate. In the first study, all patients enrolled in the self-medication program and giving their consent to participate in the study were included in the sample. The exclusion of the patients who did not pass the cognitive assessment was not appropriate because these patients should have also been enrolled in the program, and the impact of the approach on their condition should be studied as well. Regarding the second study, the description of the criteria for inclusion was insufficient, whereas the gender and demographic background of the participants were not discussed, and the specific disease and received education on treatment were consciously disregarded.
The sampling size of 220 patients for the study by Grantham et al. (2006) and 115 patients for the study by Maloney & Weiss (2008) was appropriate for achieving the specific research goals and avoiding data redundancy. Taking into account the scope of the research questions, it can be stated that it was not the size but the variation parameter of sampling which was the main drawback of the research design.
The informed consent of the participants was obtained in the two studies for the purpose of ensuring their rights. Moreover, due to the ethical considerations, the design of the two studies did not presuppose the control groups, and the rights of the subjects were observed.
In general, it can be concluded that the convenience sampling used in the studies conducted by Grantham et al. (2006) and Maloney & Weiss (2008) can result in biased estimates, whereas some of the criteria of inclusion and exclusion of the participants into the sample were not appropriate which can decrease the value of the achieved research results.
Reference List
Grantham, G., McMillan, V., Dunn, S. V., Gassner, L., & Woodcock, P. (2006). Patient self-medication — a change in hospital practice. Journal of Clinical Nursing, 15(8), 962-70.
Maloney, L.R., & Weiss, M. E. (2008). Patients’ perceptions of hospital discharge informational content. Clinical Nursing Research, 17, 200 – 219.
Polit, D. & Beck, C.T. (2004). Nursing research: Principles and methods. 7th ed. Philadelphia, PA: Lippincott Williams & Wilkins.
Yoon, S. & Horne, C. (2004). Accruing the sample in survey research. Southern Onlne Journal of Nursing Research, 5 (2). Web.