Selecting a Valid Survey Instrument for a Quantitative Study


Posted March 10, 2017

One of the first steps for selecting a valid survey instrument for a quantitative research topic is to narrow down the variables of interest. Has the variable already been measured in an archival data set? Or will you have to measure the variable through use of an instrument, such as a survey? If archival data is not available, then you must search for a reliable and valid survey instrument.

Reliability, also known as internal consistency, refers to the degree that a set of survey questions measure a similar characteristic. When searching for an appropriate survey instrument, Cronbach’s alpha is one of the most frequent reported statistics used to measure reliability. Applying George and Mallery’s (2016) guidelines, try to look for survey scales that meet at least the acceptable threshold of internal consistency (α = .70). After you have collected your data, statistical software like SPSS or R can quickly compute Cronbach’s alpha to make a comparison to the original findings.

Validity refers to the appropriateness of the interpretations that can be made with the survey responses. The three primary measures of validity for data collection instruments are content validity, criterion validity, and construct validity. Content validity refers to whether an instrument appears to be measuring what it is intended to measure. To assess content validity, a researcher will frequently ask recognized experts in the field to provide their opinion on the applicability of the instrument. To assess criterion validity, the measures from a previously validated instrument are compared to the new instrument. To assess construct validity, a Confirmatory Factor Analysis (CFA) is typically used to reduce the overall number of observed variables into latent factors (or constructs) based on commonalities within the data set. When searching for an appropriate survey instrument, the findings of the validity checking are typically located in the instrumentation section of the journal publications or research articles.

Google is probably the best search tool for finding a reliable and valid survey instrument. For example, if searching for an instrument to measure job satisfaction, keyword searches such as “job satisfaction scale reliability and validity” will provide potential options. It is important to cast a wide net and select the most appropriate instrument for your population and topic of interest. In addition, using the Measurement Instrument Database for the Social Sciences (MIDSS) can help to identify a survey instrument using a keyword or phrase. For more information on this database, please visit: http://www.midss.org/author justin

References
George, D. & Mallery, P. (2016). SPSS for Windows step by step: a simple guide and reference, 11.0 update (14th ed.). Boston, MA: Allyn and Bacon.


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