# What is reliability and validity in research

1. Tests that are valid are also reliable. For high stakes tests e.
2. For example, a medical thermometer is a reliable tool that would measure the correct temperature each time it is used. The ACT is valid and reliable because it measures what a student learned in high school.
3. External Reliability Internal reliability , or internal consistency, is a measure of how well your test is actually measuring what you want it to measure. There are many statistical tools you can use to measure reliability.
4. If the scores are taken at different times, then this is one way to estimate test-retest reliability ; Different forms of the test given on the same day can estimate parallel forms reliability.

Overview of Reliability and Validity Outside of statistical research, reliability and validity are used interchangeably. For research and testing, there are subtle differences. Tests that are valid are also reliable.

• For low stakes tests e;
• Several methods exist for calculating the coefficient include test-retest, parallel forms and alternate-form;
• External Reliability Internal reliability , or internal consistency, is a measure of how well your test is actually measuring what you want it to measure;
• A simple correlation between two scores from the same person is one of the simplest ways to estimate a reliability coefficient.

The ACT is valid and reliable because it measures what a student learned in high school. Reliability is a measure of the stability or consistency of test scores.

1. Some authors suggest this figure should be above 0.
2. One specific type is parallel forms reliability , where two equivalent tests are given to students a short time apart.
3. For example, a medical thermometer is a reliable tool that would measure the correct temperature each time it is used.
4. In the same way, a reliable math test will accurately measure mathematical knowledge for every student who takes it and reliable research findings can be replicated over and over. A simple correlation between two scores from the same person is one of the simplest ways to estimate a reliability coefficient.

You can also think of it as the ability for a test or research findings to be repeatable. For example, a medical thermometer is a reliable tool that would measure the correct temperature each time it is used. In the same way, a reliable math test will accurately measure mathematical knowledge for every student who takes it and reliable research findings can be replicated over and over.

There are many statistical tools you can use to measure reliability. External Reliability Internal reliabilityor internal consistency, is a measure of how well your test is actually measuring what you want it to measure.

• For low stakes tests e;
• The ACT is valid and reliable because it measures what a student learned in high school.

For example, a claim that individual tutoring improves test scores should apply to more than one subject e. A test for depression should be able to detect depression in different age groups, for people in different socio-economic statuses, or introverts.

One specific type is parallel forms reliabilitywhere two equivalent tests are given to students a short time apart. If the forms are parallel, then the tests produce the same observed results.

The Reliability Coefficient A reliability coefficient is a measure of how well a test measures achievement. It is the proportion of variance in observed scores i.

• External Reliability Internal reliability , or internal consistency, is a measure of how well your test is actually measuring what you want it to measure;
• For example, a medical thermometer is a reliable tool that would measure the correct temperature each time it is used;
• One specific type is parallel forms reliability , where two equivalent tests are given to students a short time apart;
• Reliability is a measure of the stability or consistency of test scores;
• External Reliability Internal reliability , or internal consistency, is a measure of how well your test is actually measuring what you want it to measure;
• You can also think of it as the ability for a test or research findings to be repeatable.

Several methods exist for calculating the coefficient include test-retest, parallel forms and alternate-form: A simple correlation between two scores from the same person is one of the simplest ways to estimate a reliability coefficient. If the scores are taken at different times, then this is one way to estimate test-retest reliability ; Different forms of the test given on the same day can estimate parallel forms reliability.

The Spearman Brown formula is a measure of reliability for split-half tests.

The range of the reliability coefficient is from 0 to 1. Rule of thumb for preferred levels of the coefficient: For high stakes tests e. Some authors suggest this figure should be above.

## Reliability and Validity in Research: Definitions, Examples

For low stakes tests e. Some authors suggest this figure should be above 0. Click on the link to visit the individual pages with examples for each type: