Why Classical Test Theory Matters to Me

Classical test theory focuses around a test takers testing outcome capability and is based on an equation (observed score=true score + error). The observed score is the test takers actual practical score; the true score is a test takers score without measurement errors; and error occurs through various situations including method error (testing situations) and trait error (test taker error). Method error can be reduced through reliability and objectivity while trait error can be abridged through focus, application, and scoring. One last aspect of classical test theory is random error. This form of error (random error) can be reduced by administering multiple tests to students. The final outcome equation for classical test theory is observed score=true score + method error + trait error + random error.

Applying and understanding the classical test theory will benefit your students and improve your teaching methods. This theory allows teachers to focus on their assessment tools because reliability and validity is accounted for. I have had many teachers who would distribute tests and not take into account measurement errors. These tests frustrated me and my peers because our grades were negatively affected. Teachers are performing a disservice to their students when these problems occur and it just isn’t fair! This is why I am a huge advocate of alternative assessment because the typical traditional assessment really can cause reliability and objectivity issues (method error). Most students also prefer alternative assessment because it allows them to be more expressive of their work.

Teachers need to take into account the importance of the classical test theory and its methods. Errors in measurement through tests and grading are real issues that affect our students. These issues need to be addressed but it’s difficult because many teachers don’t know anything about this theory, reliability, or even validity. Until then, error will continue to hamper our assessment tools and our students will only suffer.