On March 13, 2010, Barnett Berry spoke at the National Conference of State Legislatures' annual national education seminar. The 2010 event, focused on "What Works to Improve Education," was held in New York City at Teachers College, Columbia University. Berry led a session presenting the latest research on educator effectiveness. Research has confirmed time and again that teachers and principals are the two most important in-school factors for student achievement, especially in high-needs schools. Understanding teacher quality - how to measure it effectively and then build and spread it - is central to any viable school reform.

Berry has written (with CTQ Research and Policy Associate Alesha Daughtrey and Senior Research Consultant Alan Wieder) a companion piece to his NCSL presentation titled Teacher Effectiveness: The Conditions that Matter Most and a Look to the Future. The report considers issues in the teaching effectiveness debate, such as value added methodology, and surfaces the shortcomings of many of the most common measures of teacher effectiveness today. In one study, value added methodology was used to rank teachers in several school districts based on the gains their students attained on standardized tests in a given year. The problem was that large percentages of teachers ranked in the bottom 20% of effective teachers one year ended up in the top 20% the very next year - and vice versa. Do these teachers' effectiveness really fluctuate so wildly from year to year, or is there a problem with the measuring instrument?

Much work needs to be done to understand how to reliably measure teaching effectiveness. We understand even less about what empowers teachers to be effective in the first place, and how to spread expertise and quality where it does exist. Developing better use of research on teacher working conditions will go a long way toward building - and keeping - effective teaching in our schools. Emerging research - including case studies conducted by CTQ - is starting to point toward collective expertise and experience - for example, within a teacher team - as a strong predictor of student achievement. If these findings hold true, the closed-door culture of our classrooms has a much higher cost than feeling lonely.