Browsing by Author "Lumsden, James"

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    Person reliability
    (1977) Lumsden, James
    Person changes can be of three kinds: developmental trends, swells, and tremors. Person unreliability in the tremor sense (momentary fluctuations) can be estimated from person characteristic curves. Average person reliability for groups can be compared from item characteristic curves.
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    Test length and validity
    (1980) Bell, Richard C.; Lumsden, James
    The effect of test length on predictive validity is examined empirically by successively omitting the poorest items and by calculating the correlations between the reduced test scores and the criterion. It was found, for four tests, that the curve of validity against test length had a very gentle slope for the longer tests and that all tests could be reduced by more than 60% without appreciable decreases in validity.
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    Variations on a theme by Thurstone
    (1980) Lumsden, James
    A test model based on the Thurstone judgmental model is described. By restricting various parameters of the model, 3 Rasch models, 2 pseudo-Rasch models, 3 two-parameter ICC models, and a Weber’s Law model are derived.