Standard Setting – How Much Does the Ox Weigh?
Posted by Austin Fossey
At the Questionmark 2013 Users Conference, I had an enjoyable debate with one of our clients about the merits and pitfalls underlying the assumptions of standard setting.
We tend to use methods like Angoff or the Bookmark Method to set standards for high-stakes assessments, and we treat the resulting cut scores as fact, but how can we be sure that the results of the standard setting reflect reality?
In his book, The Wisdom of Crowds, James Surowiecki recounts a story about Sir Francis Galton visiting a fair in 1906. Galton observed a game where people could guess the weight of an ox, and whoever was closest would win a prize.
Because guessing the weight of an ox was considered to be a lot of fun in 1906, hundreds of people lined up and wrote down their best guess. Galton got his hands on their written responses and took them home. He found that while no one guess was exactly right, the crowd’s mean guess was pretty darn good: only one pound off from the true weight of the ox.
We cannot expect any individual’s recommended cut score in a standard setting session to be spot on, but if we select a representative sample of experts and provide them with relevant information about the construct and impact data, we have a good basis for suggesting that their aggregated ratings are a faithful representation of the true cut score.
This is the nature of education measurement—our certainty about our inferences is dependent on the amount of data we have and the quality of that data. Just as we infer something about a student’s true abilities based on their responses to carefully selected items on a test, we have to infer something about the true cut score based on our subject matter experts’ responses to carefully constructed dialogues in the standard setting process.
We can also verify cut scores through validity studies, thus strengthening the case for our stakeholders. So take heart—your standard setters as a group have a pretty good estimate on the weight of that ox.