What happened to BDS? Why is it missing from the Third Edition?
In the second edition of Everyday Mathematics the terms beginning, developing, and secure were used to describe both learning goals and also student performance in relation to these learning goals. Feedback from users of the second edition indicated that using the same terms to describe both the curriculum and student performance was confusing.
Teachers who have used Everyday Mathematics have various understandings of the terms beginning, developing, and secure. Some of these understandings are those that the EM authors intended; others are not. Rather than attempt to redefine existing terminology, the authors have chosen new terms. (Note that the new terminology does not reflect a fundamental change in the Everyday Mathematics approach. The new terminology is intended to clarify that approach and make it easier to implement.)