In this essay, the author tries to look forward into the 21st century to divine three things: (i) What skills will researchers in the future need to solve the most pressing problems? (ii) What are some of the most likely candidates to be those problems? and (iii) What are some current areas of research that seem mined out and should not distract…

The aim of good data graphics is to display data accurately and clearly. This definition is used as a point of departure for developing 12 rules of bad data display: (1) show as little data as possible (minimize the data density); (2) hide what data you do show (minimize the data-ink ratio); (3) ignore the visual metaphor altogether; (4) only…

Confidence envelopes for one-parameter, two-parameter, and three-parameter logistic item response models are illustrated. M-line plots showing the genesis of the envelope and the density of lines in the confidence region are described and illustrated. (Author/SLD)

A statistical method is described and illustrated which provides confidence envelopes around item response functions. Examples of 95 percent confidence envelopes for the one-, two-, and three-parameter logistic response models are given. In addition, the authors describe N-line plots, which show the genesis of the envelope as well as the density…

Simulation studies of the performance of (potentially) robust statistical estimation produce large quantities of numbers in the form of performance indices of the various estimators under various conditions. This report presents a multivariate graphical display used to aid in the digestion of the plentiful results in a current study of Item…

This paper reviews the role of the item in test construction, and suggests some new methods of item analysis. A look at dynamic, graphical item analysis is provided that uses the advantages of modern, high-speed, highly interactive computing. Several illustrations are provided. (Author/TJH)

The past decade has seen a substantial growth in methods and schemes for the display of multivariate data. This paper encompasses a sketch of the history of multivariate displays, from the pre-Columbian Quipu to Chernoff's Face; examines a number of techniques; describes their construction; illustrates their use; and comments on their efficacy.…

A test of graphicacy was developed, administered to third- through fifth-grade schoolchildren, and scored using the Rasch model. Third-grade children were much poorer at reading graphs than fourth- or fifth-grade children, but the differences between these latter two groups were modest. (Author/JKS)

A graphical-decision rule for studying an item's behavior and admitting items onto a test form is proposed. The tool--the isthmus of acceptance--ameliorates some parameter stability problems common to binary item response theory models by using a functional representation of item performance, and it is tuned to match current standards. (TJH)

Techniques of exploratory data analysis (EDA) were used to decompose data tables portraying performance of ethnic groups on the Scholastic Aptitude Test. These analyses indicate the size and structure of differences in performance among groups studied, nature of changes across time, and interactions between group membership and time. (Author/DWH)

A testlet is an integrated group of test items presented as a unit. The concept of testlet differential item functioning (testlet DIF) is defined, and a statistical method is presented to detect testlet DIF. Data from a testlet-based experimental version of the Scholastic Aptitude Test illustrate the methodology. (SLD)

A trilinear chart for understanding the distribution of achievement levels of students' performance in the National Assessment of Educational Progress (NAEP) is described and its use illustrated with data from the 1992 state NAEP mathematics assessment. Trends for all 44 participating jurisdictions are simultaneously displayed. (SLD)

Because assessment instruments of the future may well be composed of a combination of types of questions, a way to combine those scores effectively is discussed. Two new graphic tools are presented that show that it may not be practical to equalize the reliability of different components. (SLD)

Three historic examples demonstrate the vital role data displays (graphs and tables) have played in important discoveries. Levels of information that form the basis of a theory of display are described, and steps to improve the quality of tabular presentations in educational writing are outlined. (SLD)