A test is said to be valid if it measures accurately what it is supposed to measure and nothing else.

For Example;

“Is photography an art or a science? Discuss”

This is not a valid writing test .Why??

A test is said to have a face validity if it looks as it measures what it is supposed to measure. *

For Example, Oral test !!??

How ?? Show the test to colleagues and

friends.

A test is said to have a content validity if its contents constitutes a representative sample of the language skills, structures, etc with which it is concerned. *

The test should include a proper sample of the relevant structures.

How?? We need a specification of the skills or

structures that it meant to cover. * It should be clear and specific. ** Give a percentage weighting each

part.

Why is it important? Accurate measure of the what it is

supposed to measure. Harmful backwash effect. ***

Sometimes, the content of the test is determined by what is EASY to test rather what is IMPORTANT to test.

How far the results on the test agree with those provided by some independent and highly dependent assessment of the candidate’s ability.

This independent assessment is the criterion measure against which the test is validated.

Criterion-related validity

Concurrent validity Predictive validity

Concurrent validity is established when the test and the criterion are administered at about the same time.

For example; oral test How??

Random sample- subjected to the 45 mins.- 4 scorers.

If the test is not valid, then it can not be used as a dependable measure of achievement with respect to the objectives of the test.

The criterion for concurrent validation is not necessarily a proven, long test. A test might be validated against teacher’s assessment of their students provided that the assessments themselves can be relied on.

Predictive validity concerns the degree to which a test can predict candidates’ future performance.

For example, proficiency testThe criterion here might be an assessment of the students’ English as perceived by his/her supervisor at the university or it could be the outcome of the course (pass/fail).

A test is said to have a construct validity if it can be demonstrated that it measures just the ability which it is supposed to measure.

The word “construct” refers to any underlying ability which is hypothesized in a theory of language ability.

How?It is a matter of empirical research to establish whether or not such a distinct ability exists, can be measured and is indeed measured in that test.

Is it appropriate for practical test situations???

Gross, commonsense construct like “the reading ability” and “ the writing ability” have no problem since we can measure them directly.

even without evidence from research, we can be confident that we are measuring a distinct and meaningful ability.

However, we can not be sure if we are going to test them indirectly. In this case, we have to look to the theory of writing ability for guidance on how to construct the test.

For example, multiple- choice test for writing.

How??- Pilot test- Obtain extensive samples of the

writing ability of the group.- Score them.- Compare pilot test against writing

scores.- Level of agreement.

However, we might develop a satisfactory indirect test of writing, but we have administered the reality of the underlying constructs (e.g. punctuation) ???

How?? Administered a series of specially

constructed tests measuring each of the constructs by a number of different methods.

Writing can be scored separately in regard to each hypothesized construct.

If the coefficients between the scores on the same construct are higher than those on different constructs, we have evidence that we are indeed measuring separate and identifiable constructs.

Write explicit specifications for the test.

(constructs that will be measured, include representative sample of the content)

Use direct testing. make sure that the scoring of

responses related directly to what is being tested.

Make it reliable. It can not be valid unless it is reliable.