Testing and Assessment Reliability and Validity



Testing and Assessment Reliability and Validity

Reliability in Assessment

Reliability decides that how consistently the results produce in different scenarios. If it has high reliability, it exhibits steady outcomes. Four principle ways are there to find reliability of the measure:

Inter observer: It is decided by level to which observers judge the same project, presentation, or other performances on over all marking on provided elements.

Parallel form: It is observed by measuring the level of similar kind of the same test items or performances performed at two several times provide result.

Test Retest: It is indicated by examining the level to which two different measurement of skill or knowledge gives analogous results.

Split Half Reliability: It predicts by matching two different halves of test items to which level they yield general result.

Reliability in Testing

Test Reliability indicates to the marks consistency that is received on various forms of related tests. Due to dissimilarity in content being tested on various forms, human error such as student error, environmental aspects, fatigue or any other factor that may cause an error in responding, will ultimately lead to un identical results consistently. Even if the same study is conducted of the same group of students consistently for two days they will produce different scores that will not perfectly coincide. Majorly measurement errors are caused due to the following factors

Checker concentration, fatigue or careless marking etc

Tricky questions in the test, poor directions given or confusing test pattern etc

Nonuniform scoring guidelines counting or computational errors etc.

Reliability is the consistency of marking in different times or between examiners. It is important to keep in mind that it pertains to score but not people. Hence it is recommended to utilize test with good reliability measures, so test score give more than average random errors. Some factors of reliability are;

Noisy environment

Illness

Inability to understand test instructions

Questions with ambiguous words

Improper directions in testing

Uncomfortable surrounding

Mental disturbance or improper concentration

Length of assessment

Terminologies and phrases of the questions

Suitability of tasks and questions according to topic

Validity in Assessment

Validity is described as the degree to which any instrument measures what it was intended to measure. If any instrument does not remain reliable at any time, automatically it becomes invalid. Instrument can be unreliable and invalid it can be reliable but not valid or may be both reliable and valid

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There are three primary methods of test validity such as;

Content Validity: It validates that content sample being measured is represented. Pattern of the content must represent proper test items. It also relates to the level to which instrument measures the content of interest.

Criterion Validity: Targets the measurement accuracy by comparing the result with valid measure of its kind. For example, test score on admission test for university should be matched with defined criteria

Construct validity: It validates to which extent the instrument measures theoretical construct that it is meant for. Its validity can be obtain by representation of comparative test results. It is a continuous process as one updates theory according to need, to predict about scores ...