Current affiliation: Educational Testing ServiceSubject: StatisticsPrimary location: United States
Published in:ETS Research Report SeriesPublication date:2014-08-12
A Generalization of Pythagoras's Theorem
When regression models incorporate predictors that are correlated there is no unique way of defining the contribution of each predictor to the over...
Published in:ETS Research Report SeriesPublication date:2014-09-15
What Differential Weighting of Subsets of Items Does and Does Not Accomplish
I use a generalization of Pythagoras's theorem to explain the consequences of weighting in combining part scores or item scores. I use a geometric ...
Published in:ETS Research Report SeriesPublication date:2017-07-18
Unidimensional Vertical Scaling in Multidimensional Space
An example dataset is analyzed and the results used to demonstrate that a cross-grade (vertical) scale can be developed for an assessment for which...
Published in:Statistical Models for Test Equating, Scaling, and LinkingPublication date:2009-01-01
Describes designs for scaling assessments,and appropriate statistical procedures, across grade levels in schools .
Published in:Journal of Educational MeasurementPublication date:1988-09-01