Reliability is the trait of consistency with which it measure whatever is measured. For example: A speedometer of a car, when it indicates 110, it means that the car is traveling at a speed of 110 kilometers per hour. Regardless rain, sunshine or thunderstorms, the speedometer always indicates the car's traveling speed. Not the height above sea level, not the humidity, nor temperature or rainfall.

Assessment reliability is the consistency with which certain traits and attributes are assessed. Thus, a personality questionnaire consistently evaluate personality traits, an interest questionnaire interest… and so forth… well at least theoretically speaking. However, in a practical situation reliability in assessments is not always accurately and consistently possible, because there are always a number of human factors influencing the reliability of assessment results, such as…

  • motivation,
  • stress,
  • fatigue,
  • noise,
  • past assessment experiences,
  • future expectations, …etc.

…that obviously impact on measurement reliability, either in a positive or negative manner. Thus, assessment reliability - at best - is MERELY an excellent indicator of the presence (or absence) of certain traits or attributes… at the current moment. Despite assessment reliability, assessment results cannot be regarded as the “ultimate” or “true amount” of a characteristic, trait or attribute that is, was and will be present in the umwelt of the individual.

An assessor must be able to rely on the relevancy and accountability of assessment results produced by any kind of assessment instrument. There must be the certainty that processed and calculated results obtained, is a fair and relatively accurate indication or representation of the attributes/traits being assessed. In the absence of assessment reliability, the validity of such an assessment instrument is seriously jeopardized and highly questionable.

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  • Last modified: 13 September, 2018 @ 9:44pm
  • by Jan Viljoen