The last stage is “proficiency-expertise.” In this stage, proficient
learners, with increasing experience, construct sufficient
contextual information and organize their knowledge base for a
problem situation that includes some domain-specific principles.
They conceptualize a sufficient problem space in all three dimensions
that accommodates the real features of a given problem
situation. The probability of resolving a problem markedly increases.
Proficient learners sometimes represent a relatively small
but efficient knowledge structure in which sufficient key concepts
are well organized (good structural and semantic dimensions with
a surface dimension that is lacking). These knowledge structures
are in accord with the idea that experts sometimes create mental
models that contain an “optimal” rather than “maximum” number
of concepts and relations