In the 1996 NAEP mathematics assessment, teachers were asked how many hours of professional development they had received in the previous 12 months. Nationally, 28% of the fourth graders in the sample had teachers who had received 16 or more hours of professional development in mathematics; for eighth graders, the percentage was 48. In 16 states, over half the eighth graders were taught by mathematics teachers who had received that much professional development.⁹¹

The number of states requiring that teachers participate in professional development activities for renewal of certification has been on the increase over the past decade. Currently, only Hawaii, Illinois, New Jersey, New Mexico, and New York do not have a policy on professional development for renewing certification. In half the states the policy is 6 semester credits every five years. Several states have higher requirements. North Carolina requires 15 credits every five years, and in Oregon, teachers must earn 24 quarter hours in their first three years of teaching.⁹²

In an effort to encourage teachers to extend their professional development efforts, 30 states have adopted incentives for teachers certified by the National Board for Professional Teaching Standards, such as portability of certification, certification renewal, fee supports, and pay supplements.⁹³ Standards for National Board certification are available in mathematics for teachers of students ages 11 to 15. Certification at the elementary school level is general. Teachers seeking a certificate must submit a portfolio documenting their classroom practice and must go to an assessment center for a one-day series of exercises in which they demonstrate their knowledge of mathematical content and analyze student work.

There is a growing body of evidence suggesting that states and local districts “interested in improving student achievement may be well-advised to attend, at least in part, to the preparation and qualifications of the teachers they hire and retain in the profession.”⁹⁴ A qualitative and quantitative analysis of data from a 50-state survey of policies, state case study analyses, the 1993–94 Schools and Staffing Surveys, and NAEP identified the percentage of teachers with full certification and a major in the field they teach as a strong and consistent predictor of student achievement in mathematics, considerably stronger than such factors as class sizes, pupil-teacher ratios, state per-pupil spending, or teachers’ salaries.⁹⁵ This link between teacher qualification and student achievement raises the question of how good that achievement is.