This collection of four papers deals with problem solving and the measurement of problem solving. "Climbing Up the Competence Ladder: Some Thoughts on Meaningful Assessment of Problem-Solving Tasks in the Classroom" by K. C. Cheung uses the metaphor of a competence ladder to represent the problem-solving continuum with progressive qualitative bands. "A Bane or a Boon?: Meaningful Assessment of Problem-Solving Activities in the Classroom" by K. C. Cheung and L. C. Mooi explores different ways of assessing problem-solving activities and describes a conceptual framework for problem-solving processes. ""On Meaningful Measurement: Stages of Lower Secondary Pupils' Abilities in Solving Algebra Word Problems" by W. F. Loh and K. C. Cheung outlines the critical steps experienced by 130 eighth-graders in Singapore in solving word problems and explains how these activities could be assessed. "On Meaningful Measurement: Metacognition and Hierarchical Modelling of Errors in Algebra Word Problems" by K. C. Cheung and W. F. Loh analyzes the main types of errors made by 130 eighth-graders at different performance levels. A 43-item list of references is included. An appendix contains the algebra test from the fourth study. (SLD)