Definitions and Key Components 1. Evaluation of convergent validity — Tests designed to measure the same construct should correlate highly amongst themselves. 2. Evaluation of discriminant (divergent) validity — The construct being measured by a test should not correlate highly with different constructs. 3. Trait-method unit- Each task or test used in measuring a construct is considered a trait-method unit; in that the variance contained in the measure is part trait, and part method. Generally, researchers desire low method specific variance and high trait variance. 4. Multitrait-multimethod — More than one trait and more than one method must be used to establish (a) discriminant validity and (b) the relative contributions of the trait or method specific variance. This tenet is consistent with the ideas proposed in Platt's concept of Strong inference (1964).John R. Platt (1964). "Strong inference". Science 146 (3642). 5. Truly different methodology — When using multiple methods, one must consider how different the actual measures are. For instance, delivering two self-report measures are not truly different measures; whereas using an interview scale or a psychosomatic reading would be. 6. Trait characteristics — Traits should be different enough to be distinct, but similar enough to be worth examining in the MTMM. Analysis of the MTMM Matrix Typically, the respondent must answer at least three different questions (i.e. traits) measured using at least three different methods. This model has been used to estimate the quality of thousands of survey questions, in particular in the frame of the European Social Survey. One can consult these estimates through the Survey Quality Predictor software, available at sqp.upf.edu 
Definitions and key components Evaluation of convergent validity – Tests designed to measure the same construct should correlate highly amongst themselves. Evaluation of discriminant (divergent) validity – The construct being measured by a test should not correlate highly with different constructs. Trait-method unit- Each task or test used in measuring a construct is considered a trait-method unit; in that the variance contained in the measure is part trait, and part method. Generally, researchers desire low method specific variance and high trait variance. Multitrait-multimethod – More than one trait and more than one method must be used to establish (a) discriminant validity and (b) the relative contributions of the trait or method specific variance. This tenet is consistent with the ideas proposed in Platt's concept of Strong inference (1964).John R. Platt (1964). "Strong inference". Science 146 (3642). Truly different methodology – When using multiple methods, one must consider how different the actual measures are. For instance, delivering two self-report measures are not truly different measures; whereas using an interview scale or a psychosomatic reading would be. Trait characteristics – Traits should be different enough to be distinct, but similar enough to be worth examining in the MTMM. Analysis Typically, the respondent must answer at least three different questions (i.e. traits) measured using at least three different methods. This model has been used to estimate the quality of thousands of survey questions, in particular in the frame of the European Social Survey. One can consult these estimates through the Survey Quality Predictor software, available at sqp.upf.edu .
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Key Components
key components
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6. Trait characteristics —
Trait characteristics –
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of the MTMM Matrix
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