Reliability and validity of assessment

A problem still lies with those areas of learning which are more difficult to assess, such as diagnosis and solution of problems and the implementation of solutions, the ability to make and take opportunities and the ability to be creative. Higher levels of learning become progressively more difficult to assess on these grounds. With objective a statement of what a learner is expected to learn by the end of a training course,expressed in terms which are specific, measurable, attainable, relevant and time-bound. testing there tends to be little variation produced by the assessment instrument itself, assuming it is well formulated. This means that questions should not be ambiguous or allow guessing to yield the desired answer. With restricted and extended responses however, the learner can interpret the question in many ways and answer in many more ways that are different. The result is a lack of consistency in marking. As questions become less objective, the answers become more subjective. It may be argued therefore that objective testing is more valid. Even if the assessment instruments are thought to be valid, there are many other factors which may affect the learners’ performance, e.g. personality influences, ‘tactics’, gender and social differences, etc. It is very difficult to achieve total reliability and validity because of these factors.


Reliable assessment allows one to make reliable comparisons across groups and over time, and objective testing is justly popular since it may approach this goal, within reason. Objective testing is, however, the least valid way to assess a learner’s ability to analyse, synthesize and evaluate. The answer is to use as many forms of assessment as possible depending on the resources and time available. Evidence of learning should be collected from a wide variety of sources, ranging from standardized tests to daily informal observations.


Therefore, the purpose of assessment is to enable the teacher or trainer to ‘know’ the learner, and to allow the learners and teachers to know themselves. However, the results of assessment are frequently used as a means of selection for future education or employment. What is inferred about a learner by a ‘grade’? A learner who achieves a norm-referenced ‘B’ has proven to be ‘better than’ some of the others, but at what? Similarly, a learner who achieves a number of set criteria has proved to be capable of these, but what else can he or she do?