Impact evaluation and measurement are highly complex and can pose challenges for both social impact providers and funders. Measuring the impact of social interventions requires the continuous exploration and improvement of evaluation approaches and tools. This article explores the available evidence on meta-evaluation--the "evaluation of…

This article explores a number of key issues with regard to the measurement of creativity in the course of conducting psychological research or when applying various evaluation measures. It is argued that, although creativity is a fuzzy concept, it is no more difficult to investigate than other fuzzy concepts people tend to take for granted. At…

This paper presents myths as well as facts about value-added analysis. These myths include: (1) "Value-added isn't fair to teachers who work in high-need schools, where students tend to lag far behind academically"; (2) "Value-added scores are too volatile from year-to-year to be trusted"; (3) "There's no research behind value-added"; (4) "Using…

The literature on bibliometric indices for assessing scholarly impact, in particular the "h" index (Hirsch, 2005) and its many variants, is extensive, but nevertheless Ruscio and colleagues (this issue) succeed in making a valuable contribution. They have made the effort of collecting publication and citation data for no less than 1,750…

This study critically investigates the suitability of United Nations' composite indices and other related measures--among which the Gender Inequality Index just released in 2010--to capture gender inequalities in the context of "highly developed" countries, focusing on the case of Europe. Our results indicate that many of the gender gaps…

This commentary examines the role of the unit from the perspective of the definition of measurement in physics as the ratio of two magnitudes, one of which is defined as the unit; it is an important and timely contribution to measurement in the social sciences. There are many different points that could be commented upon, but the author will…

Ruscio and colleagues (Ruscio, Seaman, D'Oriano, Stremlo, & Mahalchik, this issue) have done a great service by systematically comparing indices of scholarly impact. Three aspects of their work are particularly valuable: (1) Their assessment of the proliferating collection of metrics, whose development has become something of a cottage industry,…

Compared to traditional test theory, where person measures are typically referenced to the distribution of a population, item response theory allows for a much more meaningful interpretation of measures as they can be directly compared to item locations. However, Stephen Humphry shows that the crucial role of the unit of measurement has been…

In their article Ruscio et al. (Ruscio, Seaman, D'Oriano, Stremlo, & Mahalchik, this issue) present a comparative study of some of the different variants of the "h" index. The study evaluates a total of 22 metrics, including the "h" index and "h"-type indices, as well as other conventional measures. The novelty of their work is to a large extent…

Humphry (this issue) deserves credit for drawing attention to the long-neglected fact that differences in item discrimination parameters are often due to empirical factors and not the product of random error components. In doing so, Humphry offers a psychometrically elegant, coherent, and practically important new model that is more flexible while…

Why do we continue to see evidence that nonprofit staff feel like outcome measurement is missing important aspects of their work? Based on an analysis of over 1,000 pages of material in 10 outcome measurement guides and a focused literature review of frontline work in three types of nonprofit organizations, this article shows that existing outcome…

Humphry (this issue) has written a thought-provoking piece on the interpretation of item discrimination parameters as scale units in item response theory. One of the key features of his work is the description of an item response theory (IRT) model that he calls the logistic measurement function that combines aspects of two traditions in IRT that…

Behavioral scientists have struggled with units of measurement for as long as they have struggled with measurement itself. Psychology's sole attempt at an explicit unit of measurement--the Lexile Framework for Reading (Stenner, Burdick, Sanford, & Burdick, 2006)--has been and continues to be ignored by the psychometric "cognoscenti."…

The purpose of this article is to examine the role of the unit in physics in order to clarify the role of the unit in psychometrics. Based on this examination, metrological conventions are used to formulate the relationship between discrimination and the unit of a scale in item response theory. Seminal literature in two lines of item response…

This article presents Stephen Humphry's response to the commentaries for his article "The Role of the Unit in Physics and Psychometrics." The commentaries covered a range of important considerations and implications. Given that the author fully agrees with the majority of the content, attention will be confined mainly to points that call…