An approach to assessment is described that allows students to understand and help decide the criteria for good work. It is called "negotiable contracting." Negotiable contracting makes assessment a highly individualized process that recognizes the subtly different ways in which students master skills. Students and teachers jointly create a ratings chart called a rubric. The rubric specifically identifies and ranks the criteria for assessing students' performance. Inside the rubric the criteria for each level of achievement are explained in detail, along with the weight to be given to each skill. Students involved in developing a rubric are more clear about the skills they need to master a lesson and how well they are progressing. As added reinforcement of the lesson, students work cooperatively in small groups to try out their ideas. The rankings used in a rubric should be neutral words that avoid the implication of failure inherent in a generalized A-F or numerical grade. The rubric should also have an even number of ratings to eliminate the temptation to award a middle ranking. Along with the rubrics developed for individual lessons, each student's assessment should encompass a look at the progress the student has made during the year. Examples of work should be collected into a portfolio for an end-of-the-year assessment. It is critical to the success of negotiable contracting to have the understanding and support of parents, who are probably more familiar with a traditional grading system. (Contains three tables.) (SLD)