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Module 3: Ensuring Validity

What is Reliability?

❶In order to have external validity, the claim that spaced study studying in several sessions ahead of time is better than cramming for exams should apply to more than one subject e.

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Together, they are at the core of what is accepted as scientific proof, by scientist and philosopher alike. By following a few basic principles, any experimental design will stand up to rigorous questioning and skepticism. The idea behind reliability is that any significant results must be more than a one-off finding and be inherently repeatable.

Other researchers must be able to perform exactly the same experiment , under the same conditions and generate the same results.

This will reinforce the findings and ensure that the wider scientific community will accept the hypothesis. Without this replication of statistically significant results , the experiment and research have not fulfilled all of the requirements of testability. This prerequisite is essential to a hypothesis establishing itself as an accepted scientific truth. For example, if you are performing a time critical experiment, you will be using some type of stopwatch.

Generally, it is reasonable to assume that the instruments are reliable and will keep true and accurate time. However, diligent scientists take measurements many times, to minimize the chances of malfunction and maintain validity and reliability.

At the other extreme, any experiment that uses human judgment is always going to come under question. Human judgment can vary wildly between observers , and the same individual may rate things differently depending upon time of day and current mood. This means that such experiments are more difficult to repeat and are inherently less reliable.

Reliability is a necessary ingredient for determining the overall validity of a scientific experiment and enhancing the strength of the results. Debate between social and pure scientists, concerning reliability, is robust and ongoing. Validity encompasses the entire experimental concept and establishes whether the results obtained meet all of the requirements of the scientific research method. For example, there must have been randomization of the sample groups and appropriate care and diligence shown in the allocation of controls.

Internal validity dictates how an experimental design is structured and encompasses all of the steps of the scientific research method. Even if your results are great, sloppy and inconsistent design will compromise your integrity in the eyes of the scientific community. Internal validity and reliability are at the core of any experimental design. External validity is the process of examining the results and questioning whether there are any other possible causal relationships.

Control groups and randomization will lessen external validity problems but no method can be completely successful. This is why the statistical proofs of a hypothesis called significant , not absolute truth. Any scientific research design only puts forward a possible cause for the studied effect.

There is always the chance that another unknown factor contributed to the results and findings. This extraneous causal relationship may become more apparent, as techniques are refined and honed. In order for research data to be of value and of use, they must be both reliable and valid. Reliability refers to the repeatability of findings. If the study were to be done a second time, would it yield the same results? If so, the data are reliable.

If more than one person is observing behavior or some event, all observers should agree on what is being recorded in order to claim that the data are reliable. Reliability also applies to individual measures.

When people take a vocabulary test two times, their scores on the two occasions should be very similar. If so, the test can then be described as reliable. To be reliable, an inventory measuring self-esteem should give the same result if given twice to the same person within a short period of time. IQ tests should not give different results over time as intelligence is assumed to be a stable characteristic. Validity refers to the credibility or believability of the research.

Are the findings genuine? Is hand strength a valid measure of intelligence? Almost certainly the answer is "No, it is not. The answer depends on the amount of research support for such a relationship. Internal validity - the instruments or procedures used in the research measured what they were supposed to measure.

As part of a stress experiment, people are shown photos of war atrocities. After the study, they are asked how the pictures made them feel, and they respond that the pictures were very upsetting.

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Issues of research reliability and validity need to be addressed in methodology chapter in a concise manner. Reliability refers to the extent to which.

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Research Reliability Reliability refers to whether or not you get the same answer by using an instrument to measure something more than once. In simple terms, research reliability is the degree to which research method produces stable .

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What is Validity? Validity encompasses the entire experimental concept and establishes whether the results obtained meet all of the requirements of the scientific research method. Reliability and Validity. In order for research data to be of value and of use, they must be both reliable and valid.. Reliability.

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You are here: AllPsych > Research Methods > Chapter Test Validity and Reliability Test Validity and Reliability Whenever a test or other measuring device is used as part of the data collection process, the validity and reliability of that test is important. Reliability is consistency across time (test-retest reliability), across items (internal consistency), and across researchers (interrater reliability). Validity is the extent to which the scores actually represent the variable they are intended to.