standards and should thoroughly document application of the process for each assessment. Doing so will make it easier for the board to maintain the highest possible validity for the resulting assessments and to provide evidence suitable for independent evaluation of that validity.

Recommendation 5-3: The NBPTS should conduct research to determine whether the reliability of the assessment process could be improved (for example, by the inclusion of a number of shorter exercises in the computer-based component) without compromising the authenticity or validity of the assessment or substantially increasing its cost.

Recommendation 5-4: The NBPTS should collect and use the available operational data about the individual assessment exercises to improve the validity and reliability of the assessments for each certificate, as well as to minimize adverse impact.

Recommendation 5-5: The NBPTS should revisit the methods it uses to estimate the reliabilities of its assessments to determine whether the methods should be updated.

Recommendation 5-6: The NBPTS should periodically review the assessment model to determine whether adjustments are warranted to take advantage of advances in measurement technologies and developments in the teaching environment.

The board’s founders envisioned that NBPTS certification would become a widely recognized credential, that districts and states would value board-certified teachers, and that the numbers of certified teachers would grow. The founders expected that board-certified teachers would become a significant presence, helping to increase the influence of the board standards by serving as leaders and mentors to other teachers. From the 1993-1994 school year, when the program began operation, to the 2006-2007 school year, 99,300 teachers have attempted to earn board certification, and 63,800 teachers have been successful.

These numbers represent approximately 3 percent of the 3.1 million NBPTS-eligible teachers in the country, and it is likely that some of those who obtained board certification will have retired or allowed their certification to lapse. While NBPTS participants represent a small fraction of the teachers in this country, the absolute volume of teachers who have pursued board certification is considerable. Moreover, the numbers of participants