Under the generalizability-theory (G-theory) framework, the estimation precision of variance components (VCs) is of significant importance in that they serve as the foundation of estimating reliability. Zhang and Lin advanced the discussion of nonadditivity in data from a theoretical perspective and showed the adverse effects of nonadditivity on…

The 0.70 and 0.80 reliability standards, proposed by Jum Nunnally, are widely employed across a spectrum of research domains. Nonetheless, due to their arbitrary nature, both standards fail to satisfy the needs of researchers. This paper presents a set of formulas that can be used to compute minimum reliability standards as a function of a…

Research Findings: We evaluated the score stability of the Mathematical Quality of Instruction (MQI), an observational measure of mathematics instruction. Three raters each scored, independently, 100 video-recorded lessons taught by 20 kindergarten teachers in the spring. Using generalizability theory analyses, we decomposed the MQI's score…

Purpose of the Study: Missing data are a common problem encountered while implementing measurement instruments. Yet the extent to which reliability, validity, average discrimination and difficulty of the test results are affected by the missing data has not been studied much. Since it is inevitable that missing data have an impact on the…

Rubrics are widely used in higher education to assess performance in project-based learning environments. To date, the sources of error that may affect their reliability have not been studied in depth. Using generalisability theory as its starting-point, this article analyses the influence of the assessors and the criteria of the rubrics on the…

Problem Statement: In addition to being teaching tools, concept maps can be used as effective assessment tools. The use of concept maps for assessment has raised the issue of scoring them. Concept maps generated and used in different ways can be scored via various methods. Holistic and relational scoring methods are two of them. Purpose of the…

Direct Behavior Rating-Multi-Item Scales (DBR-MIS) have been developed as formative measures of behavioral assessment for use in school-based problem-solving models. Initial research has examined the dependability of composite scores generated by summing all items comprising the scales. However, it has been argued that DBR-MIS may offer assessment…

In adolescence research, the treatment of measurement reliability is often fragmented, and it is not always clear how different reliability coefficients are related. We show that generalizability theory (G-theory) is a comprehensive framework of measurement reliability, encompassing all other reliability methods (e.g., Pearson "r,"…

One method to investigate classroom quality is for a person to observe what is happening in the classroom. However, this method raises practical and technical concerns such as how many observations to collect, when to collect these observations and who should collect these observations. The purpose of this study is to provide empirical evidence to…

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…

Intraclass correlation coefficients (ICCs) are commonly used in behavioral measurement and psychometrics when a researcher is interested in the relationship among variables of a common class. The formulas for deriving ICCs, or generalizability coefficients, vary depending on which models are specified. This article gives the equations for…

Observational methods are increasingly being used in classrooms to evaluate the quality of teaching. Operational procedures for observing teachers are somewhat arbitrary in existing measures and vary across different instruments. To study the effect of different observation procedures on score reliability and validity, we conducted an experimental…

The purpose of this study was to investigate the methods of estimating the reliability of school-level scores using generalizability theory and multilevel models. Two approaches, "student within schools" and "students within schools and subject areas," were conceptualized and implemented in this study. Four methods resulting from the combination…

Self- and peer assessments are becoming more popular in classrooms, but there are few data on the reliability and validity of such assessments performed by school children. Because these factors are greatly affected by the number of raters, we conducted two studies to determine the rating behaviours of teenagers in self- and peer assessments, and…

In 1997, noting that the 50th anniversary of the publication of "Coefficient Alpha and the Internal Structure of Tests" was fast approaching, Lee Cronbach planned what have become the notes published here. His aim was to point out the ways in which his views on coefficient alpha had evolved, doubting now that the coefficient was the best way of…