Characteristics of Good Evaluation Instrument

Characteristics of Good Evaluation Instrument - Validity, Reliability, Objectivity, Practicability, Comprehensiveness, Adequacy, Comparability , Objective Basedness and Discriminating Power.

1. Characteristics of Good E valuation I nstrument Suresh Babu . G Assistant Professor CTE CPAS Paippad , Kottayam Objectivity Reliability Validity Utili Adequacy

2. Validity Reliability Objectivity Adequacy Discrimination Power Practicability Comparability Utility Characteristics of Good Evaluation Instrument Comprehensiveness Objective - Basedness

3. Validity The validity of a test may be defined as the accuracy with which the test measures what it purports to measure. According to Garrett, “The validity of a test depends upon the fidelity with which it measures what it intends to measure” Every test is constructed for some specific purpose, and it is valid only for that purpose.

4. Types of Validity There are various types of validity 1. Face Validity – It implies that a test measures superficially what the test-maker desires to measure, and not what it actually measures. This type of validity has very little significance. 2. Content Validity – It refers to the degree to which a test sample the content area which is to be measured. 3. Predictive Validity – It refers to the extent to which a test can predict the future performance of individuals.

5. 4 . Concurrent Validity – It refers to the relationship between scores on a measuring tool and a criterion available at the same time. The concurrent validity differs from predictive validity only on time dimension. 5 . Construct Validity – It refers to the extent to which a test reflects, constructs presumed to underlie the test performance and also the extent to which it is based on theories regarding these constructs. Types of Validity

6. Method of Determining validity of a test Method of determining validity of an achievement test are: Correlating it with another test Correlating with teacher rating Analyzing the test to ensure that due weightage has been given to content and objective. Item-analysis

7. Reliability Reliability of a test is the consistency with which the test measures whatever it does measure. A reliability test is a thrust worthy test. A reliability test should yield essentially the same (or almost same) scores when administered a second time to the same pupils, provided no learning or forgetting has taken place between the periods of the two testing. The degree of reliability is usually denoted by a coefficient of correlation / reliability coefficient

8. Reliability depends on the following factors: Appropriateness and definiteness of the task. Consistency, stability, alertness or fatigued state of the pupil who takes the test. Consistency and objectivity of the scorer of the test Reliability

9. Method of Determining Reliability There are several methods to determine the reliability of a test: Test-Re-Test Method :- The same test is administrated twice to the same group of students with a given time interval between the two administration of the test. With the help of these two sets of scores, correlation is computed to find the stability. Parallel Form Method :- Used only in case where two forms of the test have been prepared. It is truly equivalent tests – with same number of items, uniformity in content, etc

10. 3. Split-Half-Method :- It is the method of splitting the test into two half and finding the correlation between the two. 4. Rational Equivalent Method :- The method utilizes two forms of tests with inter-changeable corresponding items and inter item correlations. Method of Determining Reliability

11. Objectivity A test is objective if the score assigned by different but equally competent score is not affected by the judgment, personal opinion or bias of the scorers. Objectivity is the opposite of subjectivity. Objectivity is a pre-requisite of reliability and therefore of validity

12. Objectivity of a test may be increased by: Using more objective-type test items Making essay type test-tests more exact and clear Preparing a marking scheme or scoring key. Setting realistic standards Using the average score of two independent examiners who evaluated the test. Objectivity

13. Adequacy Adequacy of a test means sufficiency and suitability of that test. A good test should include items measuring the objectives and content.

14. Discrimination Power A test should be able to discriminate the respondents on the basis of the phenomena measured . Here Bad items are eliminated and good items are retained. A good item is one which is attempted successfully by 50% children. A good item must discriminate between superior children and backward children. Suppose an item is successfully answered by all children, that item is a bad item with no discrimination power

15. Method of Discrimination Power Divide the group which pilot sampling is applied into two groups, upper and lower groups. Take the item, say, item number one, and find out how many of upper group have done it correctly. Find out how many of the lower group have done it correctly Convert the difference in the number of correct responses from two groups into an index, using the formula D.P = U-L/N , U and L are the number of correct responses in the upper and lower groups, N is the number of cases in each group If discrimination power is very low and very high it is eliminated The discrimination power ranging between 0.4 to 0.8 are included in the test. Now the test is ready

16. Practicability If all the criteria is satisfied to conduct a test, but from the practical point of view, it may not be possible to conduct such a test. Economy of time, effort, number of personnel and finance required also has to be of utmost concern for the planner of a test.

17. Comparability A test possesses comparability when the scores obtained by administering can be interpreted in items of a common base that has a natural or accepted meaning. Two methods for establishing comparability are: Making available equivalent forms of a test Making available adequate norms

18. Utility A test has utility if it provides the test conditions that would facilitate realization of the purpose for which it is meant. For achieving utility it is essential that the test is constructed in the light of well-through-out purpose and its interpretations are used in obtaining desirable results

19. Objective - B asedness Evaluation is making judgement 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.

20. Comprehensiveness It refers to the degree to which a test contains a fairly wide sampling of items to determine the objectives or abilities so that the resulting scores are representatives of the relative total performance in the areas measured.