Testing and Assessment - Reliability and Validity
Oct 10, Reliability and validity of the Relationship Assessment Scale Results from this study support previously published studies in chronic pain. Reliability and Validity of Measurement Then a score is computed for each set of items, and the relationship between the two sets of scores is examined. Reliability and validity are two concepts that are important for defining and and you should be able to help parents interpret scores for the standardized exams.
Similarly, we want questions that get accurate responses from respondents - this is validity. Reliability Reliability refers to a condition where a measurement process yields consistent scores given an unchanged measured phenomenon over repeat measurements.
Perhaps the most straightforward way to assess reliability is to ensure that they meet the following three criteria of reliability. Measures that are high in reliability should exhibit all three. Test-Retest Reliability When a researcher administers the same measurement tool multiple times - asks the same question, follows the same research procedures, etc. This is really the simplest method for assessing reliability - when a researcher asks the same person the same question twice "What's your name?
If so, the measure has test-retest reliability. Measurement of the piece of wood talked about earlier has high test-retest reliability.
Understanding Assessment: Reliability and Validity
Inter-Item Reliability This is a dimension that applies to cases where multiple items are used to measure a single concept.
In such cases, answers to a set of questions designed to measure some single concept e. Interobserver Reliability Interobserver reliability concerns the extent to which different interviewers or observers using the same measure get equivalent results.
If different observers or interviewers use the same instrument to score the same thing, their scores should match. For example, the interobserver reliability of an observational assessment of parent-child interaction is often evaluated by showing two observers a videotape of a parent and child at play. These observers are asked to use an assessment tool to score the interactions between parent and child on the tape. If the instrument has high interobserver reliability, the scores of the two observers should match.
Validity To reiterate, validity refers to the extent we are measuring what we hope to measure and what we think we are measuring. How to assess the validity of a set of measurements? A valid measure should satisfy four criteria. Face Validity This criterion is an assessment of whether a measure appears, on the face of it, to measure the concept it is intended to measure. This is a very minimum assessment - if a measure cannot satisfy this criterion, then the other criteria are inconsequential.
We can think about observational measures of behavior that would have face validity. For example, striking out at another person would have face validity for an indicator of aggression. Similarly, offering assistance to a stranger would meet the criterion of face validity for helping. However, asking people about their favorite movie to measure racial prejudice has little face validity. Content Validity Content validity concerns the extent to which a measure adequately represents all facets of a concept.
Consider a series of questions that serve as indicators of depression don't feel like eating, lost interest in things usually enjoyed, etc. If there were other kinds of common behaviors that mark a person as depressed that were not included in the index, then the index would have low content validity since it did not adequately represent all facets of the concept.
Criterion-Related Validity Criterion-related validity applies to instruments than have been developed for usefulness as indicator of specific trait or behavior, either now or in the future. Validity tells you if the characteristic being measured by a test is related to job qualifications and requirements. Validity gives meaning to the test scores. Validity evidence indicates that there is linkage between test performance and job performance. It can tell you what you may conclude or predict about someone from his or her score on the test.
If a test has been demonstrated to be a valid predictor of performance on a specific job, you can conclude that persons scoring high on the test are more likely to perform well on the job than persons who score low on the test, all else being equal.
Validity also describes the degree to which you can make specific conclusions or predictions about people based on their test scores. In other words, it indicates the usefulness of the test.Reliability VS Validity
Use only assessment procedures and instruments that have been demonstrated to be valid for the specific purpose for which they are being used. It is important to understand the differences between reliability and validity.
Validity will tell you how good a test is for a particular situation; reliability will tell you how trustworthy a score on that test will be. You cannot draw valid conclusions from a test score unless you are sure that the test is reliable. Even when a test is reliable, it may not be valid. You should be careful that any test you select is both reliable and valid for your situation. A test's validity is established in reference to a specific purpose; the test may not be valid for different purposes.
For example, the test you use to make valid predictions about someone's technical proficiency on the job may not be valid for predicting his or her leadership skills or absenteeism rate. This leads to the next principle of assessment. Similarly, a test's validity is established in reference to specific groups. These groups are called the reference groups.
The test may not be valid for different groups. For example, a test designed to predict the performance of managers in situations requiring problem solving may not allow you to make valid or meaningful predictions about the performance of clerical employees. If, for example, the kind of problem-solving ability required for the two positions is different, or the reading level of the test is not suitable for clerical applicants, the test results may be valid for managers, but not for clerical employees.
Test developers have the responsibility of describing the reference groups used to develop the test. The manual should describe the groups for whom the test is valid, and the interpretation of scores for individuals belonging to each of these groups.
You must determine if the test can be used appropriately with the particular type of people you want to test.
Validity and Reliability
This group of people is called your target population or target group. Use assessment tools that are appropriate for the target population. Your target group and the reference group do not have to match on all factors; they must be sufficiently similar so that the test will yield meaningful scores for your group. For example, a writing ability test developed for use with college seniors may be appropriate for measuring the writing ability of white-collar professionals or managers, even though these groups do not have identical characteristics.
In determining the appropriateness of a test for your target groups, consider factors such as occupation, reading level, cultural differences, and language barriers.
Recall that the Uniform Guidelines require assessment tools to have adequate supporting evidence for the conclusions you reach with them in the event adverse impact occurs. A valid personnel tool is one that measures an important characteristic of the job you are interested in.
Use of valid tools will, on average, enable you to make better employment-related decisions. Both from business-efficiency and legal viewpoints, it is essential to only use tests that are valid for your intended use. In order to be certain an employment test is useful and valid, evidence must be collected relating the test to a job. The process of establishing the job relatedness of a test is called validation.
Methods for conducting validation studies The Uniform Guidelines discuss the following three methods of conducting validation studies. The Guidelines describe conditions under which each type of validation strategy is appropriate. They do not express a preference for any one strategy to demonstrate the job-relatedness of a test. Criterion-related validation requires demonstration of a correlation or other statistical relationship between test performance and job performance.
In other words, individuals who score high on the test tend to perform better on the job than those who score low on the test. If the criterion is obtained at the same time the test is given, it is called concurrent validity; if the criterion is obtained at a later time, it is called predictive validity. Content-related validation requires a demonstration that the content of the test represents important job-related behaviors. In other words, test items should be relevant to and measure directly important requirements and qualifications for the job.
Construct-related validation requires a demonstration that the test measures the construct or characteristic it claims to measure, and that this characteristic is important to successful performance on the job.
The three methods of validity-criterion-related, content, and construct-should be used to provide validation support depending on the situation. These three general methods often overlap, and, depending on the situation, one or more may be appropriate.
French offers situational examples of when each method of validity may be applied. First, as an example of criterion-related validity, take the position of millwright. Employees' scores predictors on a test designed to measure mechanical skill could be correlated with their performance in servicing machines criterion in the mill. If the correlation is high, it can be said that the test has a high degree of validation support, and its use as a selection tool would be appropriate.
Second, the content validation method may be used when you want to determine if there is a relationship between behaviors measured by a test and behaviors involved in the job. For example, a typing test would be high validation support for a secretarial position, assuming much typing is required each day.
If, however, the job required only minimal typing, then the same test would have little content validity.
Content validity does not apply to tests measuring learning ability or general problem-solving skills French, Finally, the third method is construct validity.
This method often pertains to tests that may measure abstract traits of an applicant. For example, construct validity may be used when a bank desires to test its applicants for "numerical aptitude. To demonstrate that the test possesses construct validation support, ". Professionally developed tests should come with reports on validity evidence, including detailed explanations of how validation studies were conducted. If you develop your own tests or procedures, you will need to conduct your own validation studies.
As the test user, you have the ultimate responsibility for making sure that validity evidence exists for the conclusions you reach using the tests. This applies to all tests and procedures you use, whether they have been bought off-the-shelf, developed externally, or developed in-house. Validity evidence is especially critical for tests that have adverse impact.
When a test has adverse impact, the Uniform Guidelines require that validity evidence for that specific employment decision be provided. The particular job for which a test is selected should be very similar to the job for which the test was originally developed.
Determining the degree of similarity will require a job analysis. Job analysis is a systematic process used to identify the tasks, duties, responsibilities and working conditions associated with a job and the knowledge, skills, abilities, and other characteristics required to perform that job. Job analysis information may be gathered by direct observation of people currently in the job, interviews with experienced supervisors and job incumbents, questionnaires, personnel and equipment records, and work manuals.
In order to meet the requirements of the Uniform Guidelines, it is advisable that the job analysis be conducted by a qualified professional, for example, an industrial and organizational psychologist or other professional well trained in job analysis techniques. Job analysis information is central in deciding what to test for and which tests to use. Using validity evidence from outside studies Conducting your own validation study is expensive, and, in many cases, you may not have enough employees in a relevant job category to make it feasible to conduct a study.
Therefore, you may find it advantageous to use professionally developed assessment tools and procedures for which documentation on validity already exists. However, care must be taken to make sure that validity evidence obtained for an "outside" test study can be suitably "transported" to your particular situation.