Robert Marzano on Conducting Accurate Teacher Evaluations

(Originally titled “Reducing Error in Teacher Observation Scores”)

In this Educational Leadership article, author/consultant Robert Marzano notes two types of error that can occur when evaluating teachers: 

• Measurement error, which occurs when the person observing doesn’t adequately understand classroom dynamics or the scoring tool. This can be remedied by training.
• Sampling error, when the observer doesn’t see a teacher’s usual behavior. Lots of unannounced visits are the way to counteract this problem.

Marzano goes on to suggest five ways that administrators can evaluate teachers more accurately:

• Use teacher self-evaluation. If the teacher’s assessment is the same as the administrator’s, “that’s a good indication that the observer rating is accurate,” says Marzano. If there are discrepancies, it’s time for discussion and further observation.

• Make a point of observing the three different lesson types. Marzano suggests planning visits to see lessons that introduce new content, those in which students practice and deepen their understanding, and those that require students to apply what they’ve learned.

• Make frequent unannounced visits. This allows the administrator to collect information and resolve any uncertainties about teacher performance.

• Make random videos of teachers. Raters can score tapes independently, and teachers can be involved too.

• Let teachers challenge scores. Teachers should be able to produce evidence to argue with summative scores they feel are inaccurate, says Marzano. 

“Reducing Error in Teacher Observation Scores” by Robert Marzano in Educational Leadership, November 2012 (Vol. 70, #3, p. 82-83), www.ascd.org 

From the Marshall Memo #460