National and international standards documents are calling for science teachers to teach their students how to engage in the practices of science. Previous studies have found that most science teachers do not have the knowledge and skill to do this because they have not had experience engaging authentically in science. One way to overcome this problem is for science teachers to participate in short-term Research Experiences for Teachers. However, few studies have looked at teachers' learning of science skills and practices in such experiences, and almost all have relied primarily on data self-reported by the teachers. In our previous studies we found that there is good reason to find these self-reported data suspect. Therefore, in this study we investigated the low calibration of teachers' self-reports of their abilities to engage in research skills and practices and their abilities as measured by knowledgeable others, and here we suggest several reasons for this low calibration.