The Arc's Self-Determination Scale: Procedural Guidelines

pervasive, if not clearly articulated, mistrust of self-report
measures with people with mental retardation based on
several factors. Practitioners and researchers have tended
to dismiss personal reports from such individuals as
unreliable. Individuals with mental retardation were seen
as intellectually incompetent and this incompetence
extended to the individuals’ reports of beliefs, emotions,
feelings, or perceptions. Their opinions and perceptions
were not accorded value and worth and were not solicited
or encouraged (p. 528).
Within a competence model of disability, however, the beliefs,
opinions and perceptions of people with disabilities become
“increasingly important and valued, not imbued with assumptions
of incompetence” (Wehmeyer, 1994a). Difficulties in
measurement remain, but the importance of individuals’ beliefs
about themselves and their environments make the effort
worthwhile.
The limited research that exists suggests that people with
disabilities hold perceptions of control that are more external, and
thus more maladaptive, than non-disabled peers. Students with
learning disabilities (Dudley-Marling, Snider & Tarver, 1982) and
mental retardation (Wehmeyer, 1994b) have been found to have
more external scores than non-disabled peers, even when
compared to same age peers who experienced school failure but
were not receiving special education services. Such maladaptive
perceptions were found to contribute to ineffective career decisionmaking
for youth with mental retardation and learning disabilities
(Wehmeyer, 1993). Wehmeyer (1994c) also found that adults with
cognitive and developmental disabilities who were competitively
employed held significantly more adaptive or internal perceptions
of control than did peers who worked in sheltered environments or
who were unemployed.
The role of educators in promoting internal perceptions of
control, as well as adaptive efficacy and outcome expectations, a
positive self-awareness and a realistic self-knowledge, is more
complex than just providing adequate instructional experiences.
An internal locus of control emerges as children make choices
about things that they do every day, like selecting clothing, and
these choices are honored and supported. To understand
contingency relations between their actions and positive outcomes,
children have to learn to distinguish between outcomes due to
ability, effort and chance. There is a typical developmental course
for this progression. Very young children attribute positive
outcomes solely to effort and do not take into account ability or
chance. As they get older, children begin to distinguish between
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