Starting with descriptors: One starting point is to consider what you wish to describe, and
then write, collect or edit draft descriptors for the categories concerned as input to the
qualitative phase. Methods 4 and 9, the first and last in the qualitative group below, are
examples of this approach. It is particularly suitable for developing descriptors for
curriculum-related categories such as communicative language activities, but can also
be used to develop descriptors for aspects of competence. The advantage of starting
with categories and descriptors is that a theoretically balanced coverage can be
defined.
Starting with performance samples. The alternative, which can only be used to develop
descriptors to rate performances, is to start with representative samples of
performances. Here one can ask representative raters what they see when they work
with the samples (qualitative). Methods 5–8 are variants on this idea. Alternatively, one
can just ask the raters to assess the samples and then use an appropriate statistical
technique to identify what key features are actually driving the raters’ decisions
(quantitative). Methods 10 and 11 are examples of this approach. The advantage of
analysing performance samples is that one can arrive at very concrete descriptions
based on data.
The last method, No 12, is the only one to actually scale the descriptors in a
mathematical sense. This was the method used to develop the Common Reference
Levels and illustrative descriptors, after Method 2 (intuitive) and Methods 8 and 9
(qualitative). However, the same statistical technique can be also used after the
development of the scale, in order to validate the use of the scale in practice, and
identify needs for revision.
Intuitive methods:
These methods do not require any structured data collection, just the principled
interpretation of experience.
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