Characteristics of a Good Evaluation Tool
1. Objective-basedness: Evaluation is making judegement about some phenomena or performance on the basis of some pre-determined objectives. Therefore a tool meant for evaluation should measure attainment in terms of criteria determined by instructional objectives. This is possible only if the evaluator is definite about the objectives, the degree of realization of which he is going to evaluate. Therefore each item of the tool should represent an objective.
2. Comprehensiveness: A tool should cover all pints expected to be learnt by the pupils. It should also cover all the pre-determined objectives. This is referred to be comprehensiveness.
3. Discriminating power: A good evaluation tool should be able to discriminate the respondents on the basis of the phenomena measured. Hence while constructing a tool for evaluation, the discrimination power has to be taken care of. This may be at two levels- first for the test as a whole and then for each item included.
4. Reliability: Reliability of a tool refers to the degree of consistency and accuracy with which it measures what it is intended to measure. If the evaluation gives more or less the same result every time it is used, such evaluation is said to be reliable. Consistency of a tool can be improved by limiting subjectivity of all kinds. Making items on the basis of pre-determined specific objectives, ensuring that the expected answers are definite and objective, providing clearly spelt-out scheme for scoring and conducting evaluation under identical and ideal condition will help in enhancing reliability. Test-retest method, split-half method and equivalent form or parallel form method are the important methods generally used to determine the reliability of a tool.
5. Validity: Validity is the most important quality needed for an evaluation tool. If the tool is able to measure what it is intended to measure, it can be said that the tool is valid. It should fulfill the objectives for which it is developed. Validity can be defined as “ the accuracy with which it measures what it is intended to measure or as the degree in which it approaches infallibility in measuring what it purports to measure Content validity, predictive validity, construct validity, concurrent validity, congruent validity, factorial validity, criterion-related validity, etc. are some of the important types of validity which is needs to fulfill by a tool for evaluation.
6. Objectivity: A tool is said to be objective if it is free from personal bias of interpreting its scope as well as in scoring the responses. Objectivity is one of the most primary pre-requisites required for maintaining all other qualities of a good too.
7. Practicability: A tool, however, well it satisfies all the above criteria, may be useless unless it is not practically feasible. For example, suppose, in order to ensure comprehensiveness, it was felt that thousand items should be given to be answered in ten hours. This may yield valid result, but from practical point of view it s quite impossible.