A comprehensive evaluation of a hypertext model for teaching process writing at the junior high and high school level was conducted over an 8-week period. The purpose of the study was to determine how two teachers and three different age groups of students used and reacted to the model, specifically, its embedded design features of model stories, note cards, idea buttons, mini-lessons, branching buttons, and cut-and-paste tools. Researchers sought to investigate the extent to which the embedded features facilitated the process approach, the degree to which their usage improved writing products, and any age of gender differences in patterns of use or reactions. Data collection instruments used in the study included: observer notes; frequency of embedded feature usage (automatically collected by the computer from every student during each session); holistic writing assessment; student questionnaires and interviews; teacher interviews; problem-solving analysis; and weekly records analyzing student writing. Students were asked first to use the model to compose an ending to a familiar story, then to write two stories of their own over the next 5 weeks. Results showed that applications of the embedded features varied based on teacher attitudes, feature attributes (e.g., ease of use and appeal), and student characteristics. The high school teacher and students made more usage of many of the features, and they were more likely to offer criticism of navigational aspects of the model and of the model's value as a writing aid. No significant writing improvement or gender difference was detected. The implications of the results are discussed regarding the instructional design and classroom implementation of new technologies for teaching process writing strategies. The continuing challenge for instructional designers is effectively integrating the new delivery strategies to fit classroom conditions and curriculum needs. Possible system improvements include incorporation of more word processing elements as well as security and networking arrangements for safer and easier file management. The model might also be revised to allow more instruction from the teacher and to restrict access to certain features to those students who have mastered relevant skills. (Contains 41 references.) (SWC)