Subjective measurement scales are used to measure nonobservable respondent characteristics in several fields such as clinical research, educational sciences, or psychology. To be useful, the scores resulting from the questionnaire must be validated; that is, they must provide the psychometric properties validity, reliability, and sensitivity. In this article, we present the validscale command, which carries out the required statistical analyses to validate a subjective measurement scale. We have also developed a dialog box, and validscale will soon be implemented online with Numerics by Stata.
BlanchetteD.2010. lstrfun: Stata module to modify long local macros. Statistical Software Components S457169, Department of Economics, Boston College. https://ideas.repec.org/c/boc/bocode/s457169.html.
2.
CrespiC. M., GanzP. A., PetersenL., CastilloA., and CaanB.2008. Refinement and psychometric evaluation of the impact of cancer scale. Journal of the National Cancer Institute100: 1530–1541.
3.
FayersP., and MachinD.2007. Quality of Life: The Assessment, Analysis and Interpretation of Patient-Reported Outcomes. 2nd ed. Chichester, UK: Wiley.
4.
GadelrabH.2010. Evaluating the Fit of Structural Equation Models: Sensitivity to Specification Error and Descriptive Goodness-of-Fit Indices.Saarbrücken, Germany: Lambert Academic Publishing.
5.
HamelJ.-F.2014. mi twoway: Stata module for computing scores on questionnaires containing missing item responses. Statistical Software Components S457901, Boston College Department of Economics. https://ideas.repec.org/c/boc/bocode/s457901.html.
6.
HamelJ.-F., SébilleV., Challet-BoujuG., and HardouinJ.-B.2016. Partial credit model: Estimations and tests of fit with pcmodel. Stata Journal16: 464–481.
7.
HardouinJ.-B.2004. loevh: Stata module to compute Guttman errors and Loevinger H coefficients. Statistical Software Components S439401, Department of Economics, Boston College. http://ideas.repec.org/c/boc/bocode/s439401.html.
8.
HardouinJ.-B.2007a. delta: Stata module to compute the Delta index of scale discrimination. Statistical Software Components S456851, Department of Economics, Boston College. https://ideas.repec.org/c/boc/bocode/s456851.html.
HardouinJ.-B.2007c. Rasch analysis: Estimation and tests with raschtest. Stata Journal7: 22–44.
11.
HardouinJ.-B., Bonnaud-AntignacA., and SébilleV.2011. Nonparametric item response theory using Stata. Stata Journal11: 30–51.
12.
ReichenheimM. E.2004. Confidence intervals for the kappa statistic. Stata Journal4: 421–428.
13.
WareJ. E.Jr., KosinskiM., and KellerS. D.1996. A 12-item short-form health survey: Construction of scales and preliminary tests of reliability and validity. Medical care34: 220–233.
