When I was corresponding with one of the authors in this issue, Emeritus Professor James Popham, I received an advertisement for his latest book in a document called “Popham eflyer”. As educationalists are wont to be, particularly those in assessment and evaluation research, I am at times somewhat distracted by the swirling notions of effect sizes in educational research. Consequently, I misread the name of the file as “Popham effect”. Effect size is a statistic that gives an estimate of the magnitude of a difference.
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