Validity and Reliability

there is no such thing as a

"valid test"

validity is

accuracy

reliability is necessary for validity

but does not guarantee validity

How is validity determined

by professional judgement, analysis is done by accumulating evidence that would suggest that an inference or use is appropriate and whether the consequences of the interpretations and uses are reasonable and fair

alternative forms

consistency of results among 2 or more different forms of a test, have to be equal and in same group

a set of test scores that are reliable are not necessarily valid

consistency of scores does not guarantee validity

A set of test scores can't be valid unless they are reliable

consistency of scores is necessary for validity

Construct related evidence of validity

constructs are variables such as a person's self esteem anxiety honesty or preservation tendencies. All these variables are constructs they are hypothetical entities that have been constructed to explain human behavior

problems with tests regarding validity

content underpepresentation, test of overall reading comprehension that doesn't incclude certain kinds of reading passages, construct irrelevant variance.

test criterion relationships

degree to which scores predict performance on some criterion variable, relationship between an assessment and another measure of the same trait.

validity is always a matter of degree

depending on the situation.

measuring reliability

different types, more than 1 way to measure reliability, correlation coefficient needs to different test. Low and high reliability

validity evidence based on test content

extent to which the assessment procedure adequately represents the content of the curricular aim being measured

valditiy evidence based on a tests internal structure

extent to which the internal organization of a test confirms an accurate assessment of the construct supposedly being measured

Validity is the most fundamental consideration

in developing and evaluating tests

Validity is the appropriateness and legitimacy of the

inferences and claims, interpretations and uses made from test scores. Is the interpretation made from the test results reasonable?

What is reliability

measure of consistency, measures whatever it measures with consistency. Uses data to make adjustments. Teachers need to discuss with families

standard error of measurment

measures consistency of an individuals performance. Uses same reporting scale thats being used with one test thats involved. Reliability increases SEM decreases, positive or negative opinion polls.

test retest

measures stability over test scores over time. Correlation coefficient between to sets of tests. No precise time limit

Hypothetical constructs

reading comprehension problem solving knowledge of world history

internal consistency

reliability represents the degree which items in a test are functioning in a similar way, homogenous manner.

Why is validity important?

teachers use the results of assessments to make decisions about students, appropriate educational decisions depend on the accuracy of educational assessment.

Valdity evidence

test content, response processes, tests internal structure, relations to other variables.

classification consistency

test results are used to classify test takers into categories, a type of test retest reliability

Validity focuses on

the accuracy of the interpretations

Validity is an overall evaluation of

the degree to which a specific interpretation of a test's results is supported.

validity evidence based on relations to other variables

the degree to which an inferred construct appears to exist and has been accurately measured for the intended use.

validity evidence based on response processes

the degree to which the cognitive processes test takers employ during a test support an interpretation for a specific test use

Validity should be determined by

the intended use of the test