7.2 Factors Influencing Reliability:
Factors Influencing Reliability:
The following factors affect the reliability.
1. Length of Test:
The longer the test is, the higher its reliability will be. This is because a longer test will measure more adequate sample of behavior and scores are less affected by chance factor or guessing.
2. Spread of Scores;
The larger the spread of score is, the higher the timate of reliability will be. This is because larger bility coefficient result when individual's position same from one testing to another. The greater s between scores reduces the possibility of shifting position.
3. Difficulty of Test:
Too easy or too difficult tests have low reliability. This is because both easy and difficult tests result in restricted spread of scores. For easy test, the scores are close together at the top. For difficult test, the scores are grouped together at the bottom. The differences among individuals are small, hence tend to be unreliable.
- Objectivity:
The standardized tests which are high in objectivity, have high reliability. A test is said to be objective if scores obtain the same results. The objective type tests have high reliability and essay type tests have low reliability. This is because scoring is not affected by personal opinion of scorer in objective type test. In essay tests scoring is affected by personal opinion of the scorer. Essay tests have low objectivity and hence low reliability.