Recent worldwide epidemiological surveys of autism conducted in 37 countries are reviewed; the median prevalence of autism is 0.97% in 26 high-income countries. Methodological advances and remaining challenges in designing and executing surveys are discussed, including the effects on prevalence of variable case definitions and nosography, of…

Cambridge Assessment has more than 20 years experience in assessing Critical Thinking (CT) in a number of diverse tests and qualifications, unrivalled by any other body within the UK. In recent years, a number of research activities have been carried out in order to support these assessments, with a focus on the validity of measurement. This paper…

"Linking" is a term given to a general class of procedures by which one represents scores X on one test or measure in terms of scores Y on another test or measure. A recent taxonomy by Holland and Dorans (2006; Holland, 2007) organizes the various types of links into three broad categories: prediction, scale aligning, and equating. In…

The article "Thinking About Linking" by Newton (2010) presents a novel philosophical perspective on the way that educational assessments should be linked. Newton starts by describing the linking framework as it was characterized in various publications and identifies a cross-cultural dimension in the definitions and uses of test…

Presents a broad definition of "testlet" and suggests a framework for classifying types of testlets. Considers several issues that bear on the conceptualization of testlets and analyses of scores from tests composed of testlets. Suggests some research topics that seem particularly important to advancing the meaningful and appropriate use…