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The Concepts of Reliability and Validity Explained With Examples All research is conducted via the use of scientific tests and measures, which yield certain observations and data.
But for this data to be of any use, the tests must possess certain properties like reliability and validity, that ensure unbiased, accurate, and authentic results.
This PsycholoGenie post explores these properties and explains them with the help of examples. PsycholoGenie Staff Last Updated: Dec 09, Reliability and validity are key concepts in the field of psychometrics, which is the study of theories and techniques involved in psychological measurement or assessment.
The science of psychometrics forms the basis of psychological testing and assessment, which involves obtaining an objective and standardized measure of the behavior and personality of the individual test taker. The data obtained via this process is then interlinked and integrated to form a rounded profile of the individual.
Such profiles are often created in day-to-day life by various professionals, e. Career counselors employ a similar approach to identify the field most suited to an individual. Such profiles are also constructed in courts to lend context and justification to legal cases, in order to be able to resolve them quickly, judiciously, and efficiently.
However, to be able to formulate accurate profiles, the method of assessment being employed must be accurate, unbiased, and relatively error-free.
In order to ensure these qualities, each method or technique must possess certain essential properties.
Concept of Reliability It refers to the consistency and reproducibility of data produced by a given method, technique, or experiment. The form of assessment is said to be reliable if it repeatedly produces stable and similar results under consistent conditions.
Consistency is partly ensured if the attribute being measured is stable and does not change suddenly. However, errors may be introduced by factors such as the physical and mental state of the examinee, inadequate attention, distractedness, response to visual and sensory stimuli in the environment, etc.
When estimating the reliability of a measure, the examiner must be able to demarcate and differentiate between the errors produced as a result of inefficient measurement and the actual variability of the true score.
A true score is that subset of measured data that would recur consistently across various instances of testing in the absence of errors. Hence, the general score produced by a test would be a composite of the true score and the errors of measurement.
Types of Reliability Test-retest Reliability It is a measure of the consistency of test results when the test is administered to the same individual twice, where both instances are separated by a specific period of time, using the same testing instruments and conditions.
The two scores are then evaluated to determine the true score and the stability of the test. This type is used in case of attributes that are not expected to change within that given time period. This works for the measuring of physical entities, but in the case of psychological constructs, it does exhibit a few drawbacks that may induce errors in the score.
Firstly, the quality being studied may have undergone a change between the two instances of testing. Secondly, the experience of taking the test again could alter the way the examinee performs.
And lastly, if the time interval between the two tests is not sufficient, the individual might give different answers based on the memory of his previous attempt. Depending on which, the medication and treatment of the patient is altered. Parallel-forms Reliability It measures reliability by either administering two similar forms of the same test, or conducting the same test in two similar settings.
Despite the variability, both versions must focus on the same aspect of skill, personality, or intelligence of the individual. The two scores obtained are compared and correlated to determine if the results show consistency despite the introduction of alternate versions of environment or test.
However, this leads to the question of whether the two similar but alternate forms are actually equivalent or not. Example If the problem-solving skills of an individual are being tested, one could generate a large set of suitable questions that can then be separated into two groups with the same level of difficulty, and then administered as two different tests.
The comparison of the scores from both tests would help in eliminating errors, if any. Inter-rater Reliability t measures the consistency of the scoring conducted by the evaluators of the test. It is important since not all individuals will perceive and interpret the answers in the same way, hence the deemed accurateness of the answers will vary according to the person evaluating them.
This helps in refining and eliminating any errors that may be introduced by the subjectivity of the evaluator. If a majority of the evaluators judge are in agreement with regards to the answers, the test is accepted as being reliable.
But if there is no consensus between the judges, it implies that the test is not reliable and has failed to actually test the desired quality. However, the judging of the test should be carried out without the influence of any personal bias.
In other words, the judges should not be agreeable or disagreeable to the other judges based on their personal perception of them. Example This is often put into practice in the form of a panel of accomplished professionals, and can be witnessed in various contexts such as, the judging of a beauty pageant, conducting a job interview, a scientific symposium, etc.
Internal Consistency Reliability It refers to the ability of different parts of the test to probe the same aspect or construct of an individual.
If two similar questions are posed to the examinee, the generation of similar answers implies that the test shows internal consistency. If the answers are dissimilar, the test is not consistent and needs to be refined.
It is a statistical approach to determine reliability.Brugha TS, Cragg D. The List of Threatening Experiences: the reliability and validity of a brief life events questionnaire. Universities in Western countries host a substantial number of international students. These students bring a range of benefits to the host country and in return the students gain higher education.
Applied Sampling/Methods of Survey Sampling. SurvMeth (3 credit hours) Instructor: James Wagner, University of Michigan and Raphael Nishimura, University of Michigan A fundamental feature of many sample surveys is a probability sample of subjects.
Reliability and validity are key concepts in the field of psychometrics, which is the study of theories and techniques involved in psychological measurement or assessment.
The science of psychometrics forms the basis of psychological testing and assessment, which involves obtaining an objective and standardized measure of the behavior and personality of the individual test taker. Results. A total of 2,, random group analyses were performed to compute the empirical false-positive rates of SPM, FSL, and AFNI; these comprise 1, one-sided random analyses repeated for parameter combinations, three thresholding approaches, .
Nigerian Psychological Research Reliability and Validity of the UCLA PTSD Reaction Index for DSM-IV 27 PTSD Reaction Index has been supported.