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    Test characteristics2   mirna's edition Test characteristics2 mirna's edition Presentation Transcript

    • TEST CHARACTERISTICSVALIDITY,RELIABILITY,PRACTICALITY &BACKWASH EFFECT Prof. Jonathan Magdalena Edited by Prof. Mirna Quintero
    • QUALITIES OF MEASUREMENTDEVICES Validity Does it measure what it is supposed to measure? Reliability How representative is the measurement? Practicality Is it easy to construct, administer, score and interpret? Backwash Does it promote positive values towards learning?
    • VALIDITYValidity refers to whether or not a test measures whatit intends to measure. A test with high validity has items closely linked to the test’sintended focus. For many certification and licensure tests thismeans that the items will be highly related to a specific job oroccupation. A test with poor validity does not measure the job-related content and competencies it ought to.Kinds of validity: content validity, construct validity,Criterion-related validity (concurrent & predictive) facevalidity.
    • KINDS of VALIDITY.1. “Content”: related to objectives and their sampling.2. “Construct”: referring to the theory underlying the target.3. “Criterion”: related to concrete criteria in the real world. It can be concurrent or predictive.- “Concurrent”: correlating high with another measure already validated.- “Predictive”: Capable of anticipating some later measure.4. “Face”: related to the test overall appearance.
    • 1. CONTENT VALIDITYTest items subject tasksContent validity refers to the connectionsbetween the test items and the subject-related tasks.The test should evaluate only the contentrelated to the field of study in a mannersufficiently representative, relevant, andcomprehensible.
    • 2. CONSTRUCT VALIDITYIt implies using the construct (concepts, ideas,notions) in accordance to the state of the artin the field. Construct validity seeksagreement between updated subject-mattertheories and the specific measuringcomponents of the test.For example, a test of intelligence nowadays mustinclude measures of multiple intelligences, ratherthan just logical-mathematical and linguistic abilitymeasures.
    • 3. CRITERION-RELATED VALIDITY Also referred to as instrumental validity, it is used to demonstrate the accuracy of a test by comparing it with another test which has been demonstrated to be valid.
    • 3.a CONCURRENT VALIDITYConcurrent validity uses statistical methods ofcorrelation to other measures (pre and post measures).Examinees who are known to be either masters or non-masters on the content measured by the test are identifiedbefore the test is administered. Once the tests have beenscored, the relationship between the examinees’ status aseither masters or non-masters and their performance (i.e.,pass or fail) is estimated based on the test.This type of validity provides evidence that the test isclassifying examinees correctly. The stronger the correlation,the greater the concurrent validity of the test is.
    • 5. PREDICTIVE VALIDITYThis is another statistical approach to validity thatestimates the relationship of test scores to anexaminees future performance as a master or non-master.Predictive validity considers the question, "How well doesthe test predict examinees future status as masters ornon-masters?" For this type of validity, the correlation thatis computed is based on the test results and theexaminee’s later performance. This type of validity isespecially useful for test purposes such as selection oradmissions.
    • 5. PREDICTIVE VALIDITYThis is another statistical approach to validity thatestimates the relationship of test scores to anexaminees future performance as a master or non-master.Predictive validity considers the question, "How well doesthe test predict examinees future status as masters ornon-masters?" For this type of validity, the correlation thatis computed is based on the test results and theexaminee’s later performance. This type of validity isespecially useful for test purposes such as selection oradmissions.
    • 4. FACE VALIDITYLike content validity, face validity is determined by areview of the items and not through the use ofstatistical analyses.Unlike content validity, face validity is not investigatedthrough formal procedures. Instead, anyone who looksover the test, including examinees, may develop aninformal opinion as to whether or not the test ismeasuring what it is supposed to measure. While it isclearly of some value to have the test appear to bevalid, face validity alone is insufficient for establishingthat the test is measuring what it claims to measure.
    • QUALITIES OF MEASUREMENTDEVICES Validity Does it measure what it is supposed to measure? Reliability How representative is the measurement? Practicality Is it easy to construct, administer, score and interpret? Backwash Does it promote positive values towards learning?
    • RELIABILITY The extent to which a test, or any measuring procedure, shows the same result on repeated trials (mostly used in research).Uses:- draw conclusions,- formulate theories, or- make claims about the generalizability of research.Conditions:agreement of independent observers able to replicatetesting procedures,ability to use instruments/procedures that produceconsistent measurements.
    • RELIABILITY – Types: Stability InternalEquivalency Interrater Intrarater sources of error
    • 1. EQUIVALENCY RELIABILITYEquivalency reliability is the extent towhich two items measure identicalconcepts at an identical level ofdifficulty. Equivalency reliability isdetermined by relating two sets oftest scores to one another to highlightthe degree of relationship orassociation.
    • 2. STABILITY RELIABILITYOr test, re-test reliability - is the agreementof measuring instruments over time.To determine stability, a test is repeated onthe same subjects at a future date. Resultsare compared and correlated with the initialtest to give a measure of stability.High stability reliability instruments can be:thermometers, compasses, measuring cups,etc.
    • 3. INTERNAL CONSISTENCYInternal consistency is the extent to which tests orprocedures assess the same characteristic, skill orquality.It is a measure of the precision between themeasuring instruments used in a study. This type ofreliability often helps researchers interpret dataand predict the value of scores and the limits of therelationship among variables. For example, analyzingthe internal reliability of the items on a vocabulary quizwill reveal the extent to which the quiz focuses on theexaminee’s knowledge of words.
    • 4. INTER-RATER RELIABILITYInterrater reliability (IRR) is the extent towhich two or more individuals (coders orraters) agree. It assesses the consistency ofhow a measuring system is implemented.IRR is dependent upon the ability of two ormore individuals to be consistent. This can beachieved with training, education andmonitoring skills.
    • SOURCES OF ERROR The examinee (is a human being) The examiner (is a human being)Examination (is designed by and forhuman beings).
    • RELATIONSHIP BETWEENVALIDITY & RELIABILITYValidity and reliability are closely related.A test can be considered valid and the measurements resulting from it not reliable.Likewise, results from a test can be reliable and not necessarily valid.
    • QUALITIES OF MEASUREMENTDEVICES Validity Does it measure what it is supposed to measure? Reliability How representative is the measurement? Practicality Is it easy to construct, administer, score and interpret? Backwash Does it promote positive values towards learning?
    • BACKWASH EFFECTBackwash (or washback) effect is thepotential effect (positive or negative)of the test on learning or on the formand content of the course. Forpedagogical considerations, this effectshould be positive by enhancing learningand promoting a favorable attitudetowards it.