Measurement Validity and Reliability and Validity Gomez,

Measurement Validity and Reliability

Reliability and Validity

Gomez, D., Haas, B., Ahmed, N. Tien, H., & Nathens, A. (2011). Disaster preparedness of Canadian trauma centres: the perspective of medical directors of trauma.

Canadian Journal of Surgery, 54(1): 9-17.

The dependent variable examined in this study was the disaster preparedness of trauma centers. The dependent variable was measured using a questionnaire which was distributed to twenty-nine trauma centers in Canada. The medical director of each trauma center was invited to respond to the questions on the instrument. The researchers then employed descriptive statistics to describe the state of preparedness based on measures within the instrument.

The question of validity is essentially does the instrument measure what it purports to measure. The issue of validity in a study has several components that may be separated into categories of internal and external validity. Elements such as face validity, content and construct validity are important considerations in any research program. Several approaches are recommended for the enhancement of validity in the research process. In considering content validity where the fit between the nominal and operational definitions are considered, the study appears to have adequate content validity (Trochim 2005). The researchers noted that they reviewed literature on disaster preparedness and based on that review identified 6 domains that were critical to disaster preparedness. Consequently, "disaster preparedness' would have adequate content validity since it was anchored in the existing theory and constructed using a highly deductive approach to variable construction. The nature of the research does not permit an adequate evaluation of other types of validity in particular concurrent and predictive validity which would be linked to specific correlational tests. There was no report on these tests and consequently it is not possible to report on these types of validity.

The opinion of medical directors was used as the independent variable to determine the state of disaster preparedness. The researchers noted that this particular approach was not anchored in theory per se but rather was based on the expert opinion of the researcher team. The team appears to be qualified to make this type of expert judgment based on the types of certification present within the group. Consequently, this variable would have adequate face validity based on the analytical strength of the research team (Kerlinger, & Lee 2000).

The dependent and independent variables were measured at the nominal level of measurement. The questions were mainly yes and no questions. These types of questions are considered to be nominal since they only provide the respondent with the ability to provide categorical responses. Categorical responses provide frequencies (Creswell, 1994). Additionally, the analysis of the data support this determination since the researchers provided descriptive statistics which provides the reader with a picture of the state of readiness based on the memory and knowledge of the medical directors.