Throughout the United States, various summer science programs for precollege students are conducted with an aim toward increasing the involvement of young people in science. Most of these programs are perceived as successful by teachers and scientists because they involve students in hands-on science activities, improve their scientific skills and confidence, and allow them the opportunity to use science to answer questions and solve problems. The work described here involves a detailed assessment of a summer National Science Foundation (NSF) Young Scholars Program, which was carried out over 2 summers. Student participants were entering 9th and 10th grade. The data used for this assessment included journals kept by teaching assistants, questionnaires administered to the participants and parents, and interviews with the participants. Analysis revealed that students perceived program success differently from teachers and program organizers. Their perception of the success of a program is directly related to whether or not their individual research project met its goals, regardless of other project activities. Designing projects that have a high likelihood of success from this perspective can be complex, but this work identified six variables that must be incorporated appropriately into the design of a project to ensure its success: (1) extent of project structure and who structures the project, faculty or student; (2) project relevance; (3) project flexibility; (4) project background research; (5) tangible results; and (6) project introduction.