Browsing by Author "Marsh, Herbert W."
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Item Confirmatory factor analyses of multitrait-multimethod data: A comparison of alternative models(1991) Marsh, Herbert W.; Bailey, MichaelAlternative models for confirmatory factor analysis of multitrait-multimethod (MTMM) data were evaluated by varying the number of traits and methods and sample size for 255 MTMM matrices constructed from real data (Study 1), and for 180 MTMM matrices constructed from simulated data (Study 2). The correlated uniqueness model converged to proper solutions for 99% (Study 1) and 96% (Study 2) of the MTMM matrices, whereas the general model typically used converged to proper solutions for only 24% (Study 1) and 22% (Study 2) of the MTMM matrices. The general model was usually ill-defined (100% in Study 1, 90% in Study 2) for small MTMM matrices with small Ns, but performed better when the size of the MTMM matrix and N were larger. Even when both models converged to proper solutions, however, parameter estimates for the correlated uniqueness model were more accurate and precise in relation to known population parameters in Study 2. Index terms: confirmatory factor analysis, construct validity, discriminant validity, LISREL, method effects, multitrait-multimethod analysis, underidentified models.Item Confirmatory factor analyses of multitrait-multimethod data: Many problems and a few solutions(1989) Marsh, Herbert W.During the last 15 years there has been a steady increase in the popularity and sophistication of the confirmatory factor analysis (CFA) approach to multitrait-multimethod (MTMM) data. This approach, however, incurs some important problems, the most serious being the ill-defined solutions that plague MTMM studies and the assumption that so-called method factors reflect primarily the influence of method effects. In three different MTMM studies, ill-defined solutions were frequent and alternative parameterizations designed to solve this problem tended to mask the symptoms instead of eliminating the problem. More importantly, so-called method factors apparently represented trait variance in addition to, or instead of, method variance for at least some models in all three studies. Further support for this counterinterpretation of method factors was found when external validity criteria were added to the MTMM models and correlated with trait and so-called method factors. This problem, when it exists, invalidates the traditional interpretation of trait and method factors and the comparison of different MTMM models. A new specification of method effects as correlated uniquenesses instead of method factors was less prone to ill-defined solutions and, apparently, to the confounding of trait and method effects. Index terms: confirmatory factor analysis, construct validity, convergent validity, correlated uniquenesses, discriminant validity, empirical underidentification, LISREL, method effects, multitrait-multimethod analysis.Item Evaluating reading diagnostic tests: An application of confirmatory factor analysis to multitrait-multimethod data(1984) Marsh, Herbert W.; Butler, SusanDiagnostic reading tests, in contrast to achievement tests, claim to measure specific components of ability hypothesized to be important for diagnosis or remediation. A minimal condition for demonstrating the construct validity of such tests is that they are able to differentiate validly between the reading traits that they claim to measure (e.g., comprehension, sound discrimination, blending). This condition is rarely tested, but multitrait-multimethod (MTMM) designs are ideally suited for this purpose. This is demonstrated in two studies based on the 1966 version of the Stanford Diagnostic Reading Test (SDRT). In each study, the application of the Campbell-Fiske guidelines and confirmatory factor analysis (CFA) to the MTMM data indicated that the SDRT subscales could be explained in terms of a method/halo effect and a general reading factor that was not specific to any of the subscales; this refutes the construct validity of the 1966 version of the SDRT as a diagnostic test. Other diagnostic tests probably suffer the same weakness and should also be evaluated in MTMM studies.Item The use of path analysis to estimate teacher and course effects in student ratings of instructional effectiveness(1982) Marsh, Herbert W.A path analytic technique is described for obtaining separate estimates of variables that are normally confounded. The particular problem involves ascertaining the relative contributions of the instructor and the course being taught in determining student ratings of teaching effectiveness. A series of six different path analytic models were used to estimate teacher and course effects, along with a variety of other parameters. The best model indicated that the effect of the teacher is about five times as large as the effect of the course and that the difference is even larger for components such as Overall Instructor and Instructor Enthusiasm. In contrast to the student rating items, background/demographic variables such as class size, students’ prior subject interest, and reason for taking a course were largely a function of the course rather than the instructor.