Writing assessments often consist of students responding to multiple prompts, which are judged by more than one rater. To establish the reliability of these assessments, there exist different methods to disentangle variation due to prompts and raters, including classical test theory, Many Facet Rasch Measurement (MFRM), and Generalizability Theory…

The R software provides packages and functions that provide data analysis in classical true score, generalizability theory, item response theory, and Rasch measurement theories. A brief list of notable articles in each measurement theory and the first measurement journals is followed by a list of R psychometric software packages. Each psychometric…

An information-correction method for testlet-based tests is introduced. This method takes advantage of both generalizability theory (GT) and item response theory (IRT). The measurement error for the examinee proficiency parameter is often underestimated when a unidimensional conditional-independence IRT model is specified for a testlet dataset. By…

We developed and evaluated an Oceanography Concept Inventory (OCI), which used a mixed-methods approach to test student achievement of 11 learning goals for an introductory-level oceanography course. The OCI was designed with expert input, grounded in research on student (mis)conceptions, written with minimal jargon, tested on 464 students, and…

The current paper on writing assessment surveys the literature on the reliability and validity of essay tests. The paper aims to examine the two concepts in relationship with essay testing as well as to provide a snapshot of the current understandings of the reliability and validity of essay tests as drawn in recent research studies. Bearing in…

Broadly conceived, reliability involves quantifying the consistencies and inconsistencies in observed scores. Generalizability theory, or G theory, is particularly well suited to addressing such matters in that it enables an investigator to quantify and distinguish the sources of inconsistencies in observed scores that arise, or could arise, over…

Recent policy has charged schools and districts with maintaining highly qualified teachers and differentiating among teachers in terms of their effectiveness (U.S. Department of Education, 2009). This emphasis has driven the development and implementation of teacher quality measures which are increasingly being used to evaluate teachers with…

In this technical report, we describe the results of a study of mathematics items written to align with the Common Core State Standards (CCSS) in grades 6-8. In each grade, CCSS items were organized into forms, and the reliability of these forms was evaluated along with an experimental form including items aligned with the National Council of…

A good test is one that has at least three qualities: reliability, or the precision with which a test measures what it is supposed to measure; validity, i.e., if the test really measures what it is supposed to measure, and practicality, or if the test, no matter how sound theoretically, is practicable in reality. These are the sine qua non for any…

A good test is one that has at least three qualities: reliability, or the precision with which a test measures what it is supposed to measure; validity, i.e., if the test really measures what it is supposed to measure; and practicality, or if the test, no matter how sound theoretically, is practicable in reality. These are the sine qua non for…

Classical test theory, item response theory, and generalizability theory all treat the abilities to be measured as continuous variables, and the items of a test as independent probes of underlying continua. These models are well-suited to measuring the broad, diffuse traits of traditional differential psychology, but not for measuring the outcomes…