Selecting an Existing Instrument for a Study
When a researcher selects an existing instrument for application in a study, several major factors must be taken into account. In the first place, preference should be given to instruments that ensure the validity and reliability of the collected data. Furthermore, the results obtained must be potentially comparable with the data collected by other researchers during previous investigations on the same or a related topic.
The reliability of an instrument is reflected in the consistency of measure, whereas validity determines the degree to which this particular instrument can reflect the item under examination. Responsiveness is another important factor in the selection of an existing instrument. This term refers to the capability of the measure to track the changes that happen to the object of study over time. Responsiveness is particularly significant in the estimation of the consequences of various medical interventions (Zohrabi, 2013).
Even though a lot of information is available regarding how to select an existing instrument, the task can be difficult. One of the most appropriate traditional approaches is to conduct a thorough review of the literature (books, journals, peer-reviewed articles, etc.) that provides detailed descriptions of different instruments and their most suitable applications. Databases and other credible online resources are also helpful in this endeavor. Traditional medical sources (such as PubMed) are not the only resources to investigate in locating an instrument—in fact, it is highly advisable to address materials from other spheres to see how an instrument can be applied in different fields, as well as identifying the field in which its application yields the best results (Mohamad, Sulaiman, Sern, & Salleh, 2015).
Locating an instrument presupposes, taking into consideration not only whether it meets the goals of the intended research but also the associated financial, ethical, and time issues related to its use.
Search for an Existing Instrument to Address the Research Question
My research question addresses the issue: “In Hispanic patients with gastric cancer, does the prevalence of chemotherapy-induced nausea and vomiting differ in patients treated with conventional medicine compared to patients who receive herbal treatment in the form of ginger?” Thus, I must select a tool that would best suit assessing the quality of life in patients who undergo cancer therapy. To obtain objective results, it is necessary to assess the situation from both the researcher’s and the patient’s perspective.
As a result, it is necessary to apply several instruments within the quantitative experimental design: The researcher must perform both a patient record survey and the Functional Assessment of Cancer Therapy (FACT). The first instrument will allow obtaining background data that will have a higher degree of validity and reliability than patient-reported information as it will be supported by evidence. Types of measures will be magnitude, duration, the occurrence of an event, and severity. However, the exclusive use of medical records as an information source does not offer an objective evaluation of vomiting connected with cancer-related therapy.
FACT offers the most suitable patient-reported outcome measure in the form of a questionnaire that will assess four aspects (physical, emotional, functional, and social) of the impact of both conventional and herbal treatment, providing a holistic picture of the patient’s state. The tool has 27 questions that use a 5-point scale (0-4), in which higher numbers indicate a better state. FACT scores have been proven to have Cronbach’s α of 0.8 or above, which shows perfect reliability while at the same time having good construct validity (Zhou et al., 2012). This allows stating that in combination with medical record research, this instrument will provide all the necessary data for the comparative assessment of the two measures under discussion.
References
Mohamad, M. M., Sulaiman, N. L., Sern, L. C., & Salleh, K. M. (2015). Measuring the validity and reliability of research instruments. Procedia-Social and Behavioral Sciences, 204(1), 164-171.
Zhou, H. J., So, J. B., Yong, W. P., Luo, N., Zhu, F., Naidoo, N.,… Yeoh, K. G. (2012). Validation of the functional assessment of cancer therapy-gastric module for the Chinese population. Health and Quality of Life Outcomes, 10(1), 145-153.
Zohrabi, M. (2013). Mixed method research: Instruments, validity, reliability and reporting findings. Theory and Practice in Language Studies, 3(2), 254-262.