Testing and Assessment - Reliability and Validity
Reliability and validity are two concepts that are important for defining and measuring bias Reliability is stated as correlation between scores of Test 1 and Test 2. How would you explain to the parent that is an acceptable coefficient?. The degree of association b/w two sets of data, or the consistency of position within the two . Briefly describe the difference between reliability and validity. Validity is whether or not you are measuring what you are supposed to be measuring, and reliability is whether or not your results are consistent. If an instrument.
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. Example Medical monitoring of "critical" patients works on this principle since vital statistics of the patient are compared and correlated over specific-time intervals, in order to determine whether the patient's health is improving or deteriorating.
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.
Difference Between Reliability and Validity
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.
Difference Between Reliability and Validity | Difference Between | Reliability vs Validity
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. It is of two types. Finally, an average is calculated of all the correlation coefficients to yield the final value for the average inter-item correlation.
In other words, it ascertains the correlation between each question of the entire test. Concept of Validity It refers to the ability of the test to measure data that satisfies and supports the objectives of the test. It refers to the extent of applicability of the concept to the real world instead of a experimental setup.
If reliability is more on consistency, validity is more on how strong the outcomes of the hypothesis are. This means the validity too is strong. Validity is categorized into four types, the conclusion, internal validity, construct validity, and external validity. The conclusion validity is focused more on the relationship between the outcome and the program. Internal validity is more on asking what kind of relationship is there between the outcome and the program.
Construct validity analyzes how strong the outcome is.
External validity is focused more on the general concept of the outcome. These are some of the differences between reliability and validity. Reliability is more on the consistency of a measurement, while validity is focused more on how strong the outcome of the program was. Reliability is easier to determine, because validity has more analysis just to know how valid a thing is.
Reliability is determined by tests and internal consistency, while validity has four types, which are the conclusion, internal validity, construct validity, and external validity. Formative Validity when applied to outcomes assessment it is used to assess how well a measure is able to provide information to help improve the program under study. If the measure can provide information that students are lacking knowledge in a certain area, for instance the Civil Rights Movement, then that assessment tool is providing meaningful information that can be used to improve the course or program requirements.
Sampling Validity similar to content validity ensures that the measure covers the broad range of areas within the concept under study. Not everything can be covered, so items need to be sampled from all of the domains. When designing an assessment of learning in the theatre department, it would not be sufficient to only cover issues related to acting. Other areas of theatre such as lighting, sound, functions of stage managers should all be included.
The Relationship Between Reliability & Validity
The assessment should reflect the content area in its entirety. What are some ways to improve validity? Make sure your goals and objectives are clearly defined and operationalized.
Expectations of students should be written down. Match your assessment measure to your goals and objectives. Additionally, have the test reviewed by faculty at other schools to obtain feedback from an outside party who is less invested in the instrument. Get students involved; have the students look over the assessment for troublesome wording, or other difficulties. If possible, compare your measure with other measures, or data that may be available.