Imagine…  A hundred students is taking a 100 item test at 3 o'clock on a Tuesday afternoon.  The test is neither difficult nor easy. So, not ALL get zero or a perfect score…  What If… this test has been administered the day before or the day after….. Will the students get the exact SAME score??

 The answer will be…NO !  Even if the conditions of administration are almost similar, and it was an objective testing, and there is no learning or forgetting has taken place during one day interval….We would not expect everyone to get the exact same score….

WHY????  Because human beings are not like that…..they simple DO NOT behave in exactly the same way in every occasion, even if the circumstances are similar.  We know that scores might be different if the test had been administered the day before. This is inevitable and we must accept it.

What we can do is…  Construct, administer, and score tests in such a way that the scores actually obtained on a test on a particular occasion are LIKELY to be VERY SIMILAR to those which would have been obtained if it had been administered to the same students with the same abilities but AT A DIFFERENT TIMES.  The more similar the scores would have been, the more reliable the test is said to be.

 Reliability is the consistency of students performance on the same test. **

Methods of measuring reliability Test/ re-test method Alternative form method Internal consistency Split- half method

Test/ re-test Method  Two sets of scores for comparison.  The same group take the same test Twice. Drawbacks:  Time (too soon/ too long) ? ** Alternative form method  It is not always available.

Internal consistency  Split half method Students take the test the usual way, but each students is given two scores. One score is for one half of the test and the second score is for the other half.

How to make tests more reliable  Take enough sample of behavior. 1 For example, Reading comprehension questions such as “Where did the thief hide the jewelry?” And “”What was unusual about the hiding place” Do NOT contribute to the reliability of the test. Why ??? 2

 Don’t allow students too much freedom. Freedom in choices. For example, writing test with different topics to choose from. a) Write a composition on tourism b) Write a composition on tourism on this country. c) Write a composition on how we might develop the tourism industry in this country. d) Discuss the following measures intended to increase the number of foreign tourists coming to this country: i) more/better advertisement and/or information. ii) Improve facilities (hotels transportations…) iii) training of personnel ( guide, hotel mangers…)

 Write unambiguous items.  Provide clear and explicit instructions.  Ensure that tests are well laid and perfectly legible.1  Students should be familiar with the format and the testing techniques.  Provide uniform and non-distracting conditions of administration.

How to ensure the reliability of the scorer  Use items that permits objective scoring.  Test as direct as possible. (not much freedom)  Provide detailed scoring key for the scorer.  Train scorers  Identify students by numbers not names.  Employ multiple independent scoring. 1

Validity and Reliability  To be valid, a test must provide accurate measurements. Therefore, it must be reliable. However,  A reliable test, however, may not be valid at all. !

 For example, A writing test which requires the students to write down the translation equivalents of 500 words in their own language. This test is reliable but not a valid writing test. There will be always a tension between reliability and validity. 1