What is reliability and validity in research

Chapter I - Introduction Introductory paragraphs Chapter I begins with a few short introductory paragraphs a couple of pages at most. The primary goal of the introductory paragraphs is to catch the attention of the readers and to get them "turned on" about the subject. It sets the stage for the paper and puts your topic in perspective. The introduction often contains dramatic and general statements about the need for the study.

What is reliability and validity in research

Making A level psychology easier Reliability and validity in psychology research Reliability It is important that psychology research can easily be repeated and yield the same results each time. Reliability refers to the extent to which the measurement of a particular behaviour is consistent.

Assessing and improving reliability In order to be able to class a test or research method as reliable, it must yield consistent results each time it is used. Of course, the exact same results will not be obtained each time as participants and situations vary, but a strong positive correlation between the results of the same test will indicate reliability.

Assessing and improving reliability of observers An observational research study using more than one observer needs to be assessed for reliability. If different observers provide significantly different observations of the same behaviour, then the data provided by those observers is unreliable.

Observer reliability can therefore be assessed by correlating the data provided by the observers.

Reliability in research

Where observer scores do not significantly correlate then reliability can be improved by: Training observers in the observation techniques being used and making sure everyone agrees with them. Ensuring behaviour categories are correctly and objectively operationalised.

What is reliability and validity in research

This means that the behaviour being observed can only be that behaviour. Assessing and improving reliability of psychology tests Psychological tests, such as self report questionnaires, need to be reliable.

They can be assessed for reliability using the split-half or test-retest methods, and if unreliable the questions can be improved until reliability is established.

The split-half method involves randomly choosing half the questions on the test and comparing the results with the other half. If there is a significant positive correlation between the two halves then the questions are reliable. However it can only be effective with large questionnaires in which all questions measure the behaviour being researched.

If the results from both presentations of the test significantly positively correlate then it is a reliable test.


The disadvantages of the test-retest method are that it takes a long time for results to be obtained, and if too long an interval has been used then the participant may have changed in themselves which may mean a test is declared unreliable when it is in fact reliable.

The advantage is that every question is checked for reliability. Validity Validity refers to the extent to which a research technique actually measures the behaviour it is claimed to measure. For example, a relationship questionnaire is not a valid measure of aggression.

Population validity refers to the extent to which the results can be generalised to groups of people other than the sample of participants used. Much psychological research uses university students as participants, e.

Social Research Methods - Knowledge Base - Construct Validity

Aschand it is difficult to say for sure that the results can be generalised to anyone other than university students. Ecological validity refers to the extent to which the task used in a research study is representative of real life. Research into eyewitness testimonyfor example, has generally lacked ecological validity as participants viewed incidents on video screens rather than in real life.

Assessing and improving validity of psychology tests Psychological tests can be assessed for validity in variety of ways including face validity, content validity, concurrent validity and predictive validity: Face validity is a subjective assessment of whether or not a test appears to measure the behaviour it claims to.

It is subjective and therefore not a particularly strong method with which to assess validity. Content validity is an objective assessment of the items in a test to establish whether or not they all relate to and measure the behaviour in question.

Concurrent validity is a comparison between two tests of a particular behaviour. One test has already been established as a valid measure of the behaviour, and the other test is the new one. If the results from both old and new tests significantly correlate then the new test is valid.

Predictive validity refers to how well a test predicts future behaviour. An example of this is a diagnostic test for a mental health problem such as depression.

If the test is a valid measure of depression and accurately diagnoses depression, then there will be a significant positive correlation between the test scores and the outcome for the patient.

It can be assessed using concurrent validity in which the test is compared with an established one, and if there is a significant positive correlation then the new test is probably a valid one.Reliability and validity explained in plain English.

Definition and simple examples. How the terms are used inside and outside of research. How do you Determine if a Test has Validity, Reliability, Fairness, and Legal Defensibility? 1 Professional Testing Inc. © PTI 1. Validity Validity is arguably. Background. Because few Japanese questionnaires assess the elderly's appetite, there is an urgent need to develop an appetite questionnaire with verified reliability, validity.

All research reports use roughly the same format. It doesn't matter whether you've done a customer satisfaction survey, an employee opinion survey, a health care survey, or a marketing research survey. Chapter 3: Understanding Test Quality-Concepts of Reliability and Validity Test reliability and validity are two technical properties of a test that indicate the quality and usefulness of the test.

These are the two most important features of a test. You should examine these features when evaluating the suitability of the test for your use.

4 Item Response Theory Item response theory is a probabilistic model that attempts to explain the response of a person to an item (Hambleton, Swaminathan, & Rogers, ; Lord.

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