During the past few years, three bad statistics have been persistently used in discussions of women in science, technology, engineering, and mathematics (STEM). The first was questionable when it was published in 1983 and has since been widely used. The second came to prominence in 2006 – and now leads an international and perhaps eternal life on the Web. The third may have made its debut in 2007. Its variants occur in popular and academic books and journals, including the 2011 Proceedings of the National Academy of Sciences.

This report presents case histories of the three bad statistics, suggests writing and editing practices which might reduce such occurrences, and provides primary sources of statistics on women in STEM.