# Validity & Reliability

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Validity & Reliability

## 1. 2. Criterion Validity

### 1.2. Checking Criterion Validity

1.2.1. Predictive validity is a measure of how well a test predicts abilities. It involves testing a group of subjects for a certain construct and then comparing them with results obtained at some point in the future. This measures what extent a future level of a variable can be predicted from a current measurement.

1.2.2. Concurrent validity measures the correlation between past measures with current measures. The past test is then referred to as the criterion.

## 3. Test- Retest/ Stability

### 3.1. Test-retest is a way of estimating reliability by giving a test to the same group of individuals twice and correlating between both sets of scores.

3.1.1. More reliable in noting student growth ofer long periods of time.

3.1.2. The longer the intervals between tests, the less reliable test-retest becomes.

## 4. 3. Construct Validity

### 4.2. Checking Construct Validity

4.2.1. Discriminant (Divergent) validity ensures that constructs that should have no relationship do not have any relationship

4.2.2. Convergent Validity helps ensure that constructs that are expected to be related are actually related.

## 5. Internal Consistency

### 5.2. Checking Internal Consistency

5.2.1. Split-halves Method- splitting the assessment in half equally and finding the correlation between these halves.

5.2.1.1. This may save time but may not be accurate due to the nature of a test to be easier in the beginning and more difficult at the end.

5.2.2. Odd-Even Reliability- splitting the assessment in half by putting even numbered problems on one page and odd numbered items on another and finding the correlation.

5.2.2.1. This may be more accurate if test question difficulty was not random.

5.2.3. Kuder -Richardson Method

5.2.3.1. Kuder- Richardson consists of several other ways of estimating the internal consistency of an assessment.

5.2.3.1.1. The more difficult method of Kuder-Richardson requires a percentage of students passing each test item.

5.2.3.1.2. The less difficult requires that you know how many items are on the assesment, the mean and it's varience to figure.

## 6. Alternate Forms / Equivalence

### 6.1. Alternate Forms/ Equivalence is an estimate of two equal forms of a test.

6.1.1. This test requires two very similar assessments given under as similar conditions as possible.

6.1.2. This eliminates practice and memory problems present with test-retest reliability measurement.