Reliability Report

The reliability of an assessment method refers

to its consistency. is also a term that is synonymous with

dependability or stability authentic, honest, true Conforming to fact and therefore worthy of

belief. Worthy of being depended on

2 ways of estimating the stability: a. The Split-half method -

involves scoring two halves (usually odd items vs. even items) of a test separately for each person and then calculating the correlation coefficient for the two set of scores. The coefficient indicates the degree to which the two halves of the test provide the same results and hence, describes the internal consistency of the test.

The reliability of the test is calculated using what is known as the Spearman- Brown prophecy formula: Reliability of test = (2 x rhalf) / (1 + rhalf) where rhalf = reliability of half of the test 100 item test: 1st half (50)

= =

(2 x 32) 64 / 39

other half (50)

/

(1 + 38)

Reliability of test = 1.64102564

b. The Kuder-Richardson

is the more frequently employed formula for determining internal consistency, particularly KR20 and KR21. KR21 = K / (K – 1) [1 {n(K-M}/K(Variance)]

where: K = number of items on the test, M = mean of the test, Variance = variance of the test scores.    

The mean of a set of score is simply the sum of the scores divided by the number of scores.

The mean of a set of score is simply the sum of the scores divided by the number of scores.

Mean

its variance is given by:

Variance = Sum of differences of individual scores and mean / n-1 where n is the number of test takers. V = / 10-1 =/9 V =

KR21 = K / (K – 1) [1 {n(K-M}/K(Variance)] KR21 = 100 / (100-1) [1 {n(100-M)/ 100 (variance)}] KR21 =

Reliability of a test may also mean the consistency of test results when the same test is administered at two different time periods. This is the test-retest method of estimating reliability. The estimate of test reliability is then given by the correlation of the two test results.

Practicality and Efficiency

Ethics in Assessment

 refers to questions of right and

wrong.

a. Teachers need to ask themselves if it is right to ask themselves if it is right to assess a specific knowledge or investigate a certain question. Here are some situations in which assessment may not be called for:   Requiring students to answer checklist of their sexual fantasies; Asking elementary pupils to answer sensitive questions

without consent of their parents;

Testing the mental abilities of pupils using an instrument

whose validity and reliability are unknown;

 

b. Webster defines ethical (behavior) as ‘conforming to the standards of conduct of a given profession or group’. Therefore, it is largely a matter of agreement among teachers.

c. Test results and assessment results are confidential. It must b between the teacher and the student concerned and not to be known to other members of the class.

d. Deception – sometimes it is necessary to conceal the objective of the assessment from the students in order to ensure fair and impartial results. The teacher has a special responsibility to : Determine whether the use of such techniques is

justified by the educational value of the assessment

Determine whether alternative procedures are

available that do not make use of concealment

Ensure that students are provided with sufficient

explanation as soon as possible.

e. The temptation to assist certain individuals in class during assessment or testing is ever present. It is best that the teacher does not administer the test himself if he believes that such concern may be considered unethical.