Some intrinsic and extrinsic factors have been proven to affect test score reliability. When designing tests, teachers have to consider these factors. These factors include; group variability, scoring reliability, test length, and item difficulty. This paper delves at discussing how each of these variables impact test design. The paper will further discuss how to mitigate those impacts.
Group variability is an extrinsic factor that affects the reliability of the test score. When the group of individuals that are being tested is homogenous in identity, it is likely that the reliability of the test scores will be lowered and vice-versa. In a group of students, the students normally differ in age, learning an ability, other factors, and as a result of this variability test score reliability is affected. Therefore, to mitigate this, teachers have to put into account all these variables when designing tests.
Delegate your assignment to our experts and they will do the rest.
Scoring reliability also can significantly affect the reliability of test scores because if tests are not scored well it would be difficult to decide if the test retake is reliable. Teachers usually grade differently, and this makes scoring reliability difficulty in grading performance, portfolio, and grading essays. Therefore, it is very significant to have objective scoring to mitigate this.
Test reliability has a definite relation with the length of the test. The longer the test or, the more the number of items the test contains, the higher the reliability of the test and vice-versa (Wells & Wollak, 2003). However, it is not easy to ensure the maximum test length to guarantee an appropriate value of reliability. In such case, the length of the test ought not to give rise to fatigue effects in the students being tested. Thus, to mitigate these effects, teachers ought to use longer tests than shorter tests. This is because shorter tests are less reliable.
Item difficulty, as well as clarity of expression of a test, also has an impact on test score reliability. The reliability of the test scores tends to be low if the test items are very easy or very difficult for the students or group members (Wells & Wollak, 2003). This is because both tests have a restricted spread of scores.
References
Wells, C. & Wollack, J. (2003). Testing and Evaluation Services. [Online]. Available at: https://testing.wisc.edu/Reliability.pdf . Accessed 6 th Dec 2018.
