7.4 Objectivity

The objectivity of a test refers to the degree to which equally competent scorers obtain the same results. Most standardized tests of aptitude and achievement are high in objectivity. The test items are of the objective type (e.g., multiple choice), and the resulting scores are not influenced by the scorers' judgment or opinion. In fact, such tests are usually constructed so that they can be accurately scored by trained clerks and scoring machines. When such highly objective procedures are used, the reliability of the test results is not affected by the scoring procedures.For classroom tests constructed by teachers, however, objectivity may play an important role in obtaining reliable measures of achievement. In essay testing the results depend to a large extent on the person doing the scoring. Different persons get different results, and even the same person may get differnet results at different times. Such inconsistency in scoring has an adverse effect on the reliability of the measures obtained, for the test scores now reflect the opinions and biases of the scorer as well as the differences among pupils in the characteristic being measured.

In the use of essay tests, for example, objectivity can be increased by careful, hrasing of the questions and by a standard set of rules for scoring. Such increased objectivity will contribute to greater reliability without sacrificing validity.