Thursday, November 03, 2011

Assessment and Evaluation

In education circles, these two flap around like much-reduced versions of Odin's ravens. Yet they are not a symmetric pair, or even orthogonal. They are linked by differences that were once obvious and are now subtle, much as 'right' and 'wrong' are, but not quite.

Assessment (from Latin assidere = 'sit down beside', 'be continually present with', 'constantly attend to'), implies that you sit down beside somebody, look over their shoulder, and decide exactly how much they score. The purpose here used to be the determination (from Latin terminus = 'boundary') of income for tax calculations (from Latin tangere = 'to touch' and calculi = 'stones'), a practice known to this day as 'assessment'. I've deliberately stressed the Latin etymology here to point out that the Romans were very heavy on tax assessment and related practices, because that is how you run a great empire administratively.

Assessment is meant to be a purely quantitative exercise. You touch up someone, estimate (from Latin aestimare = 'appraise') his wealth, and assess his tax. When we assess students, all we're looking for is their quantitative achievement so we can compare them to a chart or table and place them appropriately.

Evaluation, on the other hand, comes from a venerable linguistic stem from which we also get 'valour', 'valency' and 'value'. Also from the Latin, evaluation is about determining the potency or worth of something in its social context. When we evaluate something, we aren't looking only at its obvious quantitative attributes, but at its potential and actual usefulness or quality when compared to everything around it.

When we evaluate students, therefore, we are looking at them in terms of how much skill and potential are revealed by what they have done and are doing. We are thinking of them qualitatively, in as many dimensions as necessary to figure out how valuable they are in their present and future context.

Thus, evaluation is to assessment as sculpture is to sketching — the former needs the latter more than the latter needs the former, but it is much more well-rounded. Evaluation gives assessment a greater purpose, although assessment itself can have its own purposes.

Here's an example. Think of a physical fitness test battery. You might want to include chin-ups (to evaluate upper body strength), standing broad jump (to evaluate one form of lower body strength), juggling (to evaluate coordination), a 2.4 km run (to evaluate basic aerobic fitness), and so on. The numbers you get here form an assessment, and the methods used to obtain the numbers are called assessment rubrics.

Now consider what the entire test battery tells us about the subject's overall fitness levels and what they mean in terms of employment prospects and potential job scope. (If you had a trained observer watching the candidate's approach to taking these tests, you might also have one kind of psychological data.) Put it all together to form a narrative about this person's capabilities, and you have an evaluation.

Evaluations are too complicated to have fixed rubrics. Instead, you tell the evaluator what you are looking for, and the evaluator decides how to put the assessment data together to tell you what you will find. It requires a much higher level of cognition, and the burden of responsibility (moral or otherwise) is also much greater.

In examinations, anybody can use a marking scheme and turn in a reasonable assessment of an examinee's performance. In fact, for the so-called objective tests, a machine can do the assessment.

However, not all who get 27/40 for an MCQ test got there the same way — some may well be unusual candidates of great promise, while others may be drones who studied hard and got only the obvious questions right. It takes a trained interpreter to tell you what exactly the pattern of right and wrong answers means about the candidate, and even then, without asking a student why they chose their answers, the evaluation is very thin and may not very helpful.

In short, assessment is all about 'what do we have' and evaluation is all about 'what does it mean to us'. Assessment is simple, evaluation complex. Assessment can be a science; if it is, then evaluation is an art. And I'm quite sure I will have more to say about them.

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