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Published on: June 20, 2020
Baby Observational Selective Control AppRaisal (BabyOSCAR): Construct validity and test performance
Vanessa Maziero Barbosa1, Colleen Peyton2,3, Theresa Sukal-Moulton2,3
1Department of Occupational and Physical Therapy, University of Illinois Health, Chicago, IL, USA.
Insights
The Baby Observational Selective Control AppRaisal (BabyOSCAR) tool demonstrates strong construct validity for assessing infant movement in cerebral palsy (CP). It reliably measures arm and leg function across different ability levels.
Area of Science:
- Pediatric Physical Therapy
- Developmental Pediatrics
- Rehabilitation Science
Background:
- Assessing independent joint motion in infants with cerebral palsy (CP) is crucial for early intervention.
- The Baby Observational Selective Control AppRaisal (BabyOSCAR) is a novel assessment tool designed for this purpose.
- Evaluating the psychometric properties of new clinical assessments is essential for their reliable application.
Purpose of the Study:
- To investigate the construct validity of the BabyOSCAR assessment.
- To determine the reliability and item properties of BabyOSCAR using Rasch analysis.
- To confirm BabyOSCAR's suitability for assessing infants with and without CP.
Main Methods:
- BabyOSCAR was administered to 75 infants (45 with CP, 30 without).
- Rasch analysis and classical test theory were employed to evaluate item fit, unidimensionality, reliability, and differential item functioning.
- Cronbach's alpha was calculated to assess internal consistency.
Main Results:
- The BabyOSCAR assessment demonstrated good fit to the Rasch model, indicating sound psychometric properties.
- Unidimensionality analysis suggested two distinct dimensions: arm and leg movements.
- Reliability indices for item calibration (0.84-0.86) and infant measures (0.82-0.91) were strong, with Cronbach's alpha ranging from 0.90 to 0.95.
Conclusions:
- The BabyOSCAR assessment exhibits excellent construct validity and reliability for evaluating independent joint motion in infants.
- The tool effectively differentiates between three infant ability levels and provides an interval-level measurement scale.
- Separate arm and leg subscales are supported, offering a comprehensive assessment of motor skills.
Aim:
To investigate the construct validity of the Baby Observational Selective Control AppRaisal (BabyOSCAR), an assessment of independent joint motion in infants with cerebral palsy (CP).
Method:
BabyOSCAR was scored for 75 infants (45 with CP and 30 without CP). Rasch analysis was used in combination with classical test theory to assess areas of strength or improvement. Overall fit and precision, unidimensionality, local independence, reliability indices, Wright's child-item map, and differential item functioning were examined as part of Rasch analysis to investigate the item properties, internal construct validity, and reliability of BabyOSCAR. Cronbach's α was used to evaluate items' internal consistency.
Results:
Analysis demonstrated good fit to the Rasch model, with only one erratic item. Unidimensionality results suggest two dimensions, split between arm and leg items. Item calibration reliability was between 0.84 and 0.86, with three distinct item difficulty levels. Infant measure reliability was between 0.82 and 0.91, separating infants into three ability levels. Together, the two subscales covered the full range of skills, with redundancy mostly between the same motion on both sides of the body. Cronbach's α was between 0.90 and 0.95.
Interpretation:
BabyOSCAR's construct validity was supported. Arm and leg subscales can be translated to a logit scale.
What This Paper Adds:
Baby Observational Selective Control AppRaisal (BabyOSCAR) has excellent construct validity with good overall fit and precision. Individual BabyOSCAR items contribute and work well together, forming an interval-level assessment. BabyOSCAR has two separate subscales, arms and legs, that complement each other. BabyOSCAR's items represent a continuum of skills with three distinct difficulty levels. BabyOSCAR's continuum of skills reliably separates infants into three ability levels.
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