Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 15 Developing and Testing Self-Report Scales

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Tell whether the following statement is true or false: Scale development begins with a sound conceptualization of the construct (the latent variable) to be measured, excluding its dimensionality.

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer False Scale development begins with a sound conceptualization of the construct (the latent variable) to be measured, including its dimensionality.

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Conceptualizing the Construct Scale development begins with a sound conceptualization of the construct (the latent variable) to be measured, including its dimensionality

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Generating Items Existing instruments Research literature Concept analyses In depth studies Focus groups Clinical observations

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Domain Sampling Model Homogeneous set of items from a hypothetical universe of items

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Decisions About Item Features Number of items Response items Positive and negative stems Item intensity Item time frames

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Wording the Items—Readability Clarity Jargon Length Good wording

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins External Review by Experts Review by members of a target population Cognitive questioning

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Content Validity Conceptualize the construct Panel of experts: calculation of a quantitative index such as the CVI to summarize the experts’ judgments of the relevance of scale items.

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Once content validity has been established at a satisfactory level, the scale must be administered to a development sample. What is the typical number of respondents who are representative of the target population? A.100 B.150 C.250 D.300

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer D Once content validity has been established at a satisfactory level, the scale must be administered to a development sample—typically 300 or more respondents who are representative of the target population.

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Content Validity Satisfactory level: –Development sample –300 or more respondents representative of target population

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Tell whether the following statement is true or false: Exploratory factor analysis is used to reduce a small set of variables into a larger set of underlying dimensions, called factors.

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer False Exploratory factor analysis is used to reduce a large set of variables into a smaller set of underlying dimensions, called factors.

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Analysis of Scale Development Data Basic item analysis: Inter-item correlation Item-scale correlations Exploratory factor analysis (EFA): Factor extraction Factor rotation—orthogonal or oblique

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Illustration of Factor Rotation

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Confirmatory Factor Analysis (CFA) Involves tests of a measurement model A subset of sophisticated statistical techniques (structural equation modeling)

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Measurement Model Stipulates the hypothesized relationship between latent variables and manifest variables.

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Translating Scales Into Other Languages Centered versus decentered translations/Conceptual equivalence Semantic equivalence (back translations): – Selecting and preparing translators – Undertaking an iterative process – Testing the translated version

Copyright © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins Evidence for Semantic Equivalence and Psychometric Soundness Pretests of original and translated scale Sample of bilingual people Comparison: –Reliabilities –Factor structures –Validity estimates between two scales