Last week, the ASA Board of Directors adopted an “ASA Statement on Value-Added Models for Educational Assessment.” What the statement says, and why the ASA makes such statements, are the topics of today’s ASA at 175 blog.
As noted in the ASA’s press release on the statement, use of value-added models (VAMs) has become more prevalent, perhaps because these models are viewed as more objective or authoritative than other types of information. VAMs attempt to measure the value a teacher adds to student-achievement growth by analyzing changes in standardized test scores. VAMs are sometimes used in high-stakes decisions such as determining compensation, evaluating and ranking teachers, hiring or dismissing teachers, awarding tenure and closing schools.
The ASA position statement makes the following recommendations:
- Estimates from VAMs should always be accompanied by measures of precision and a discussion of the assumptions and possible limitations of the model.
- VAMs should be viewed within the context of quality improvement, which distinguishes aspects of quality that can be attributed to the system from those that can be attributed to individual teachers, teacher preparation programs or schools.
- The ASA endorses wise use of data, statistical models and designed experiments for improving the quality of education.
- VAMs are complex statistical models, and high-level statistical expertise is needed to develop the models and interpret their results.
The story already has been picked up in several places:
These articles, and others that will appear, reflect the controversial nature of this issue, and the ways position statements such as this one are interpreted by a writer’s position on the matter. One education writer wrote us an extremely cranky note about how “spineless” the VAMs statement was. He used several more adjectives to describe his displeasure.
The ASA is not in the business of determining educational policy, but we are very much in the business of promoting sound statistical practice. Our descriptive statement about the ASA notes that we promote “sound statistical practice to inform public policy and improve human welfare.” This statement on VAMs urges people to think carefully about the uses of these models and to engage with statistical experts, because such models require expertise to use correctly. Especially when the stakes are high, it is sensible to ensure decisions are made based on proper data and analysis. That’s what we as statisticians bring to the table.
And, that’s why we make these ASA position statements. The statistical community has long been concerned that our voice is not heard. We can’t be heard if we don’t speak up! We choose the topics for position statements carefully, and the work is member-driven. Once a topic is selected, a team of subject-matter experts writes a draft statement that is reviewed and, if acceptable, approved by the Board.
We are careful to focus on statistical issues about which we are experts. We eschew political, economic, or other aspects about which we just have our own individual opinions. We are also careful not to be speaking up on everything (there have only been about a dozen Board statements or endorsements since we began doing them in 2008), but to thoughtfully address matters for which there are experts willing to help the Board develop a position.
If there are issues you think we should address, drop a note to Steve Pierson (spierson@amstat.org), ASA Director of Science Policy. If you have kudos or criticisms about the ASA’s positions, please share them with Steve or me. While ASA members do not always agree with one another on such matters, we all are in the business together of “promoting the practice and profession of statistics.”
PS For an additional perspective on VAMs, see the article by John Ewing in AMS Notices.
In 2014, the American Statistical Association is celebrating its 175th anniversary. Over the course of this year, this blog will highlight aspects of that celebration, and look broadly at the ASA and its activities. Please contact ASA Executive Director Ron Wasserstein (ron@amstat.org) if you would like to post an entry to this blog.