The characteristics considered relevant in descriptor formulation are positiveness, definiteness, clarity, brevity and independence.
Positiveness
It is a common characteristic of assessor-orientated proficiency scales and of examination rating scales for the formulation of entries at lower levels to be negatively worded. It is more difficult to formulate proficiency at low levels in terms of what the learner can do rather than in terms of what (s)he can’t do. But if levels of proficiency are to serve as objectives rather than just as an instrument for screening candidates, then positive formulation is desirable. It is sometimes possible to formulate the same point either positively or negatively, e.g. in relation to range of language.
Example:
Positive: “has a repertoire of basic language strategies which enables him or her to deal with predictable everyday situations.”
(Eurocentres Level 3: certificate)
Negative: “has a narrow language repertoire demanding constant rephrasing and
searching for words.” (ESU Level 3)
Definiteness
Descriptors should describe concrete tasks and/or concrete degrees of skill in performing tasks. There are two points here. Firstly, the descriptor should avoid vagueness, like, for example ‘Can use a range of appropriate strategies’. What is meant by strategy? Appropriate to what? How should we interpret ‘range’? The problem with vague descriptors is that they can read quite nicely, but an apparent ease of acceptance can mask the fact that everyone is interpreting them differently. Secondly, since the 1940s, it has been a principle that distinctions between steps on a scale should not be dependent on replacing a qualifier like ‘some’ or ‘a few’ with ‘many’ or ‘most’ or by replacing ‘fairly broad’ with ‘very broad’ or ‘moderate’ with ‘good’ at the next level up. Distinctions should be real, not word-processed and this may mean gaps where meaningful, concrete distinctions cannot be made.
Clarity
Descriptors should be transparent, not jargon-ridden. Apart from the barrier to understanding, it is sometimes the case that when jargon is stripped away, an apparently impressive descriptor can turn out to be saying very little. Secondly, they should be written in simple syntax with an explicit, logical structure.
Brevity
One school of thought is associated with holistic scales, particularly those used in America and Australia. These try to produce a lengthy paragraph which comprehensibly covers what are felt to be the major features. Such scales achieve ‘definiteness’ by a very comprehensive listing, which is intended to transmit a detailed portrait of what raters can recognise as a typical learner at the level concerned, and are as a result very rich sources of description. There are, however, two disadvantages to such an approach. Firstly, no individual is actually ‘typical’. Detailed features co-occur in different ways. Secondly, a descriptor which is longer than a two clause sentence cannot realistically be referred to during the assessment process. Teachers consistently seem to prefer short descriptors. In the project which produced the illustrative descriptors, teachers tended to reject or split descriptors longer than about 25 words (approximately two lines of normal type).
Independence
There are two further advantages of short descriptors. Firstly, they are more likely to describe a behaviour about which one can say ‘Yes, this person can do this’. Consequently, shorter, concrete descriptors can be used as independent criteria statements in checklists or questionnaires for teacher continuous assessment and/or self-assessment. This kind of independent integrity is a signal that the descriptor could serve as an objective rather than having meaning only relative to the formulation of other descriptors on the scale. This opens up a range of opportunities for exploitation in different forms of assessment (see CEF, Ch. 9 Assessment).
To learn more about developing proficiency descriptors, consult Appendix A in the CEF.
On how to write scales and calibrate scale systems consult Appendix B in the CEF.