Before using a data collection instrument in the actual research study, researchers must first demonstrate internal consistency reliability. When using the same instrument, the researcher should ensure that the items on the test or data collection instrument (e.g. questionnaire) measure the same thing (Kline, 2005). The researcher can estimate this type of reliability through the split-half reliability index and coefficient alpha index (Pandey " Raghuvanshi, 2017). Coefficients of 0 and above 0.8 mean no reliability and very good reliability, respectively. Second, the researcher should demonstrate content validity which refers to the degree to which the instrument measures the construct the researcher intended to study (Bolarinwa, 2015). This type of validity relates to the degree to which scores on the test or data collection instrument agree with or predict an external criterion. Another type of validity that should be demonstrated prior to using an instrument is criterion validity. Criterion-related validity refers to the measure of how well the results of one instrument stack up against the findings of another test or predictor (Bolarinwa, 2015).
Question 2
Probability sampling would be the most appropriate technique to use for data collection on a self-esteem survey because it would ensure that every research participant an equal opportunity to be selected which consequently allows the researchers or data collector to closely estimate where an error could have occurred in the sampling process (Kline, 2005). Conversely, nonprobability sampling would not be appropriate in this particular case because it each potential participant has unknown chance of making into the representative sample and thus, the researcher cannot estimate the sampling error (Kline, 2005). Furthermore, the data collector would be expected to make accurate inferences based on the sample and therefore, probability sampling would help the researcher to draw a sample that is representative of the population from which the sample was derived. Therefore, this technique will help eliminate systematic bias in the data that will be gathered during the survey, and enable the researcher to make appropriate generalizations regarding the survey population.
Question 3
The first step establishing the reliability and validity of a data collection instrument is the collection of background information (Pandey " Raghuvanshi, 2017). The researcher establishes the purpose, objectives, questions, and hypotheses of the study, as well as determine the target population and their background. The second step is questionnaire conceptualization in which the researcher develops statements or questions for the data collection instrument from available literature. The third step, format and data analysis, involves writing the research questions and selecting appropriate scales for quantifying the participants’ responses on particular variables (Pandey " Raghuvanshi, 2017). At the end of this step, the researcher has a draft instrument (e.g. questionnaire) that is ready to establish reliability and validity.
The fourth step establishes content, construct, criterion, and face validity of the instrument. The researcher first determines whether the instrument can validly measure what it intended to measure. Second, the researcher determines if the instrument represents the content. Third, the instrument is assessed to determine if it is appropriate for the selected sample or target population. Fourth, the researcher determines if the instrument is comprehensive enough to collect all the information needed to address the purpose and goals of the study. Lastly, the instrument is examined to find out if it looks like a questionnaire (Pandey " Raghuvanshi, 2017). The final step is establishing the reliability (internal consistency, stability, and alternate form) of the instrument. After responding to the five questions in step 4 above, the researcher assesses random error in measurement through a pilot test using test-retest or split-half methods (Kline, 2005).
References
Bolarinwa, O. A. (2015). Principles and methods of validity and reliability testing of questionnaires used in social and health science researches. Nigerian Postgraduate Medical Journal, 22(4), 195.
Kline, T. J. B. (2005). Psychological testing: a practical approach to design and evaluation. Thousand Oaks, CA: Sage Publications.
Pandey, A., " Raghuvanshi, R. S. (2017). Steps in establishing reliability and validity of need assessment questionnaire on life skill training for adolescents.
