Occupational Self Assessment -- Short Form

The OSA-SF is an assessment intended to measure a person’s perceived
competence in completing Activities of Daily Living (ADLs) and Instrumental Activities
of Daily Living (IADLs) compared to the value they find in these activities. This tool is
meant to support the client by informing goal setting and treatment planning. The OSA-SF
was purposefully tailored to increase clinical utility by decreasing the length of
administration compared to the full OSA 2.2. (MOHO website)

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Area of Assessment

Assessment Type

Administration Mode

Cost

Actual Cost

Cost Description

CDE Status

Popova, E.S., Ostrowski, R.K., Wescott, J.J., Taylor, R.R. (2019). Development and validation of the Occupational Self-Assessment-Short Form (OSA-SF). The American Journal of Occupational Therapy, 73 (3). https://doi.org/10.5014/ajot.2019.030288

Populations

Key Descriptions

• The OSA SF consists of 12 items that rate self-perceived competence across areas of
  performance/participation and the degree to which an individual values each
  occupation.
• Steps for administration:
  1. Review background data
  2. Decide if the OSA-SF is appropriate
  3. Choose the appropriate setting for administration
  4. Explain the purpose and instructions to the client
  5. Client completes the OSA-SF form via self-report.
  6. Review the results with the client (discuss gaps between competence and values)
  7. Collaborate with the client to identify therapy goals and priorities.
  8. Complete the planning and implementing occupational therapy forms with the client.
  9. To gauge progress, ask the client to complete the follow-up form.
• For each of the 12 occupational areas, the client provides a competence score on a
  scale of 1-4 and a value score on a scale of 1-3.
• For the competence subscale, a raw score of 1 reflects the client is having a lot of
  difficulty with a particular occupation, while a 4 reflects the client’s belief that they
  perform an occupation extremely well.
• For the value subscale, a raw score of 1 reflects the client finds a particular
  occupation important, while a 3 reflects the client finds a particular occupation most
  important.
• Total competence scores range 0 - 48; value scores range from 0 - 36
• Based on the client’s ratings and a discussion with the therapist, the client selects up
  to 4 areas to target for improvement

Number of Items

Equipment Required

• Assessment form

Time to Administer

Required Training

Age Ranges

Instrument Reviewers

Alison Bode BA, LMT, OTS
Katie Houston BA, OTS
Amie Idicula, MA, OTS
Bethany Marshall BA, OTS
Corinne Pratt BA, OTS

ICF Domain

Measurement Domain

Considerations

Can be completed or dictated by the patient.
Requires some degree of self-awareness on the part of the patient.
Assessment is only available in the English language.

Non-Specific Patient Population

Internal Consistency

Adults in acute care (Popova, Ostrowski, Wescott & Taylor, 2019; n=86; mean
age=55.3; SD=12.0); majority African American, annual household income of less
than $40,000, and had a high school level of education or less. Convenience sample of 86 patients from acute care and acute inpatient rehabilitation. These patients varied in terms of age, diagnosis, marital status, and living situation.

• Acceptable item separation reliability. The OSA-SF demonstrated Competence and Value scales of .85 and .82
• Item separation index of 2.43 and 2.12 for Competence and Value respectively. These results make separating the scales into three distinct levels possible.
• Acceptable person separation reliability. The OSA-SF was found to have Competence and Value scales of .84 and .68 respectively.
• Person separation index of 2.29 and 1.44 for Competence and Value respectively. These results make separating the Competence scale into three distinct levels, and the Value scales into two distinct levels possible.

Criterion Validity (Predictive/Concurrent)

Inpatient Acute Care (Popova et al., 2019)

• Excellent concurrent validity between the OSA-SF and the OSA 2.2 was found for both the Competence and Value scales ( r = 0.95, p < 0.001 and r = 0.93, p < 0.001 respectively)

Construct Validity

Inpatient Acute Care (Popova et al., 2019)
The authors of the OSA-SF utilized the Rasch model in order to create the OSA-SF
from the original OSA 2.2. Items on the original OSA 2.2 that were found to not fit via
item misfit statistics were then removed in order to create the OSA-SF.

• Dimensionality: Using the OSA-SF, the Rasch model was able to determine a 46.3% variance for the Competence scale, with 8.2% of that variance explained by the second dimension. For Value, it determined a 37.2% variance, with 8% of that variance explained by the second dimension.
• Excellent item and person goodness of fit for both scales (value and competence). Of the responses from the 86 participants, 10.5% of people demonstrated misfit for the Competence scale, and 4.6% demonstrated misfit for the Value scale. This is less or similar misfit to the OSA 2.2, which demonstrated 17.4% misfit in the Competence scale, and 4.5% misfit for the value scale.
• Item hierarchy did not change from OSA-22 as a result of item removal, and OSA-22 showed acceptable fit

Floor/Ceiling Effects

Inpatient Acute Care (Popova et al., 2019)

• Adequate ceiling effects. Less than 2% of participants received the maximum possible score on the Competence and Value scales
• Excellent floor effects. 0% of participants scored the minimum possible score on the Competence and Value scales.

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