1. Abstract
The Child Occupational Self Assessment (COSA) is a client-centered, self-report evaluation tool designed to capture children’s and adolescents’ perceptions of their own occupational competence and the occupational value they assign to daily activities. Rooted theoretically in the Model of Human Occupation (MOHO) developed by Gary Kielhofner and colleagues, the COSA is engineered for individuals aged approximately 7 or 8 to 17 years who possess the cognitive capacity for self-reflection. Comprising 25 items spanning self-care, play/leisure, school tasks, and family/community engagement, the COSA utilizes a dual 4-point rating structure: one dimension rates self-perceived performance (Occupational Competence: 1 = I have a big problem doing this to 4 = I am really good at this), while the complementary dimension evaluates personal valuation (Occupational Value: 1 = Not so important to me to 4 = Most important of all to me). Visual adaptations, such as smiley faces and stars, facilitate comprehension across developmental stages and neurodivergent populations.
Extensive psychometric investigations, primarily employing Rasch measurement models (specifically Many-Facet Rasch Measurement and Rating Scale Models), demonstrate robust structural validity, unidimensionality for both competence and value constructs, acceptable item-fit statistics (infit and outfit Mean Square values generally falling between 0.7 and 1.3), and strong test-retest reliability. The COSA functions as both a quantitative outcome measurement tool and a qualitative, collaborative goal-setting mechanism that fosters shared decision-making in pediatric rehabilitation, educational support, and mental health practice.
2. Keywords
Child Occupational Self Assessment, COSA, Model of Human Occupation, MOHO, pediatric occupational therapy, occupational competence, occupational values, self-determination, Rasch analysis, client-centered assessment, goal setting, shared decision making
3. Authors
The Child Occupational Self Assessment was conceived and developed by occupational therapy scholars affiliated with the Model of Human Occupation Clearinghouse in the Department of Occupational Therapy at the University of Illinois at Chicago (UIC):
- Kaelin Baron, M.S., OTR/L — Occupational therapist and primary author of the original assessment protocols and manual development at the University of Illinois at Chicago.
- Gary Kielhofner, DrPH, FAOTA (1949–2010) — Former Professor and Wade-Meyer Endowed Chair, Department of Occupational Therapy, College of Applied Health Sciences, University of Illinois at Chicago. Kielhofner was the primary visionary behind the Model of Human Occupation.
- Anita Bundy, ScD, OT/L, FAOTA — Contributing researcher and psychometric collaborator; Professor of Occupational Therapy (affiliated with Colorado State University and University of Sydney).
- Jessica M. Kramer, PhD, OTR/L — Contributing psychometrician and author of revised versions, Rasch validation studies, and Youth Experience Survey adaptations; Associate Professor at the University of Florida.
Inquiries and authorized manuals are distributed through the MOHO Clearinghouse, Department of Occupational Therapy, College of Applied Health Sciences, University of Illinois at Chicago (Chicago, IL, USA; Web: https://moho.uic.edu).
4. Purpose
The overarching purpose of the Child Occupational Self Assessment is to establish an authentic, empowering channel through which children and adolescents can voice their subjective experiences regarding daily functioning, environmental barriers, and personal priorities. Historically, pediatric assessments in healthcare, rehabilitation, and education have relied almost exclusively on proxy respondents, including parents, classroom teachers, and clinical observers. While proxy assessments provide valuable external data regarding functional milestones and disruptive behaviors, empirical research reveals systematic discrepancies between proxy ratings and children’s self-appraisals. Children frequently identify different functional challenges, sources of frustration, and motivational goals than their adult caregivers.
The COSA addresses this gap by positioning the young client as the primary informant and active agent in their intervention planning. Clinically, the instrument serves three foundational purposes:
- Collaborative Goal Setting: By comparing a child’s ratings on Competence against their ratings on Value, practitioners identify occupational discrepancies. For example, an activity that a child rates as low competence (“I have a big problem doing this”) but high value (“Most important of all to me”) signals an immediate therapeutic priority. Conversely, low competence in an area the child considers “Not so important to me” may indicate an area where interventions could encounter resistance or disengagement.
- Facilitating Shared Decision-Making: The visual, accessible format of the COSA empowers children who have physical disabilities, learning differences, autism spectrum conditions, or psychosocial challenges to communicate directly with interdisciplinary teams, aligning therapy with self-determination theory.
- Standardized Outcome Measurement: When converted into linear interval measures via Rasch calibration tables, the COSA provides objective tracking of perceived competence and personal priorities before and after pediatric occupational therapy, mental health, or inclusive educational interventions.
5. Psychological Construct
The Child Occupational Self Assessment captures two distinct, highly interrelated psychological and occupational dimensions: Occupational Competence and Occupational Value. These constructs operationalize the internal human subsystems defined by the Model of Human Occupation.
Occupational Competence
Occupational competence reflects an individual’s subjective appraisal of their ability to sustain patterns of productive and satisfying occupational behavior across life roles. Within the COSA, competence is not measured as an external chronometric test of motor skills or cognitive aptitude; rather, it assesses the internal sense of self-efficacy, mastery, and functional ease experienced by the child. The construct spans several life domains:
- Activities of Daily Living (ADLs) and Self-Care: Evaluated through items addressing personal hygiene, clothing selection, self-maintenance, and obtaining adequate rest (e.g., Items 1, 2, 3, 5, and 23). Competence here reflects independence, motor execution, and cognitive planning.
- School and Academic Productivity: Reflected in classroom self-regulation, task completion, organizational skills, sustained attention, and peer cooperation (e.g., Items 14, 15, 16, 17, and 18). Competence in this domain signifies executive functioning, behavioral inhibition, and academic self-efficacy.
- Play, Leisure, and Community Life: Encompassing participation in active sports, quiet hobbies, fun, and autonomous navigation of community settings such as libraries, stores, and parks (e.g., Items 19, 20, 21, and 22).
- Social Communication and Interaction: Captured by relationships with peers, family cohesiveness, and interpersonal maintenance (e.g., Items 6, 7, 8, 9, 10, 11, and 12).
- Volitional Regulation and Problem Solving: Pertaining to resilience, frustration tolerance, and task persistence (e.g., Items 24 and 25).
Occupational Value
The Occupational Value construct reflects volition—the deeply personalized process by which children anticipate, choose, experience, and interpret their everyday activities. Values represent beliefs about what is good, meaningful, and important to do, serving as internal motivators for behavioral investment. In the COSA, evaluating the importance a child attaches to each occupational statement provides essential contextual insight into why particular functional limitations generate distress while others do not.
6. Theoretical Framework
The COSA is grounded directly in the Model of Human Occupation, originally formulated by Gary Kielhofner and expanded over several decades. MOHO conceptualizes human beings as open, dynamic systems that interact with their physical and social environments through purposeful activity (occupation). The internal human system is organized into three interacting subsystems: Volition, Habituation, and Performance Capacity.
Volition
Volition is the universal human drive for occupation, comprising personal causation (feelings of self-efficacy and capacity), values (commitments and beliefs about importance), and interests (dispositions toward pleasure and satisfaction). The COSA directly targets volition by eliciting the child’s explicit value framework (Occupational Value rating) and personal causation (Occupational Competence rating). Through this design, the assessment honors the child’s volitional narrative.
Habituation
Habituation represents the semi-autonomous patterns through which people organize daily behavior into predictable routines and social roles. Multiple COSA items examine habituated behaviors, such as following daily household chores (Item 13), complying with classroom rules (Item 14), maintaining study habits (Item 15), and organizing school belongings (Item 17). The scale detects breakdowns in habituation that can impede a child’s role performance as a student, peer, or family member.
Performance Capacity and the Lived Experience
Performance capacity encompasses the underlying mental and physical capabilities required to execute tasks. However, MOHO makes a critical phenomenological distinction between objective physiological/neurological capacity and the lived body experience. The COSA deliberately evaluates this lived experience: how it actually feels for the child to execute tasks in their real-world environment, navigating physical impairments, cognitive challenges, sensory overload, or social expectations.
7. Validity
Psychometric evaluations of the Child Occupational Self Assessment across diverse clinical cohorts (including children with cerebral palsy, developmental coordination disorder, learning disabilities, ADHD, psychiatric diagnoses, and typical peers) substantiate its validity as an authentic measure of children’s occupational perspectives.
Construct Validity through Rasch Measurement
Extensive Rasch analyses conducted by Keller, Kielhofner, Kramer, and colleagues (2005, 2009, 2010) demonstrated that the 25 items conform to unidimensional constructs of Occupational Competence and Occupational Value. In a seminal validation study examining 270 children (aged 7–17) with varied functional abilities, item-fit statistics confirmed strong structural coherence:
- Infit and Outfit Statistics: Mean Square (MnSq) fit indices for the Competence items clustered within the acceptable clinical psychometric range of 0.70 to 1.30, confirming that items define a coherent, single continuum of occupational difficulty.
- Item Hierarchy: Item difficulty calibrations conformed to developmental expectations. For example, self-care items such as “Physically take care of myself” and “Choose the clothes I want to wear” demonstrated lower calibrated difficulty (easily mastered by younger or impaired children), whereas higher-order executive and emotional regulation tasks such as “Keep working on something until I finish it” and “Deal with problems and frustration when things are hard” occupied higher difficulty strata.
Convergent and Discriminant Validity
Studies evaluating the relationship between the COSA and standardized external assessments show moderate, theoretically appropriate convergent correlations. Competence measures correlate significantly with the Pediatric Evaluation of Disability Inventory (PEDI) functional skills scales and the School Function Assessment (SFA) (correlations ranging from r = .38 to .56, p < .01). Importantly, divergent validity is demonstrated by low correlations (r < .25) between the child’s COSA self-report and parent proxy questionnaires regarding child internal emotional distress, affirming that children’s direct self-evaluations provide unique variance not captured by proxy observers.
8. Reliability
The COSA demonstrates sound internal consistency and temporal stability across international psychometric investigations.
- Internal Consistency: When analyzed via classical test theory, the 25-item Competence scale routinely demonstrates high internal consistency, with Cronbach’s alpha values ranging between α = .85 and α = .91 across clinical cohorts. The Value scale typically yields Cronbach’s alpha values between α = .80 and α = .88. In Rasch psychometrics, the Item Separation Index exceeds 3.0 (item reliability > .90), demonstrating that the item set consistently differentiates distinct tiers of occupational challenge.
- Person Separation Reliability: Rasch person separation reliability values for the Competence scale average approximately .78 to .84, confirming adequate precision to distinguish children with higher versus lower perceived occupational competence.
- Test-Retest Stability: In stability evaluations over a 2- to 3-week interval with clinically stable pediatric populations, intraclass correlation coefficients (ICC) range from .74 to .86 for the Competence dimension, indicating substantial reproducibility over time when no clinical interventions occur.
9. Factor Analysis
While classical Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) have been applied during international cross-cultural adaptations (such as Dutch, Swedish, and Persian translations), the primary psychometric foundation of the COSA is grounded in Item Response Theory (IRT) and Rasch analysis.
Rasch Principal Component Analysis of Residuals (PCAR)
To verify the unidimensionality assumption of the assessment, psychometricians routinely perform Principal Component Analysis on Rasch measurement residuals:
- In standard validation samples, the primary Rasch dimension accounts for more than 40% to 48% of the total variance in competence scores, which satisfies rigorous unidimensionality criteria for rehabilitation scales.
- The unexplained variance in the first contrast consistently remains below 2.0 eigenvalue units (typically between 1.4 and 1.8), indicating that systematic secondary factors or subdimensions do not contaminate the primary construct of perceived competence.
Confirmatory Structural Models
When examined through multidimensional structural equation modeling, CFA evaluations examining whether the Competence and Value scales operate as separate correlated dimensions demonstrate superior fit indices (RMSEA < .055, CFI > .93, TLI > .92) compared to a single-factor collapsed model. This confirms that children clearly distinguish between how competent they feel in an activity and how much personal value they place upon it.
10. Instrument / Measurement Tool
- Name of Instrument: Child Occupational Self Assessment (COSA)
- Alternative Forms: Available in standard youth text format, visual symbol-supported format (utilizing facial expression drawings and star icons for younger children or those with literacy challenges), and a card-sort version for tactile/interactive administration.
- Target Population: Children and adolescents aged approximately 7/8 to 17 years exhibiting mild to moderate functional, physical, or psychosocial challenges, who possess basic self-reflective abilities.
- Item Count: 25 authentic self-report items spanning self-care, play/leisure, school tasks, and family/community participation.
- Response Scale: Dual 4-point rating scale:
- Competence Dimension: 1 = I have a big problem doing this, 2 = I have a little problem doing this, 3 = I do this okay, 4 = I am really good at this (symbol version uses frown to smile faces/stars).
- Importance (Value) Dimension: 1 = Not so important to me, 2 = Important to me, 3 = Really important to me, 4 = Most important of all to me.
- Scoring and Interpretation Procedures:
- Qualitative Assessment / Goal Setting: Clinicians review items where a child reports a substantial performance gap (Competence rated 1 or 2) alongside high personal valuation (Importance rated 3 or 4). These paired discrepancies directly define client-centered intervention goals.
- Quantitative / Rasch Scoring: Raw item scores can be entered into the MOHO Clearinghouse software or Rasch-calibrated keyforms to generate linear interval measures (logits) of Occupational Competence and Occupational Value for tracking longitudinal progress.
- Reverse Scoring: Items are not reverse-coded; both scales proceed in a unipolar direction from low competence/value (1) to high competence/value (4).
- Administration Time: Approximately 20 to 45 minutes depending on the child’s developmental age, communication modality, and need for conversational elaboration.
11. Permissions & Fee and Test Year
The Child Occupational Self Assessment was formally published in manual form in 2004 (with early iterations and conceptual foundations dating to 1985 and the late 1990s) by Kaelin Baron, Gary Kielhofner, and colleagues. The assessment is copyrighted by the Model of Human Occupation Clearinghouse, Department of Occupational Therapy, College of Applied Health Sciences, University of Illinois at Chicago.
The manual, including administration instructions, reproducible assessment forms, symbol-supported cards, and Rasch conversion scoring keys, is available for purchase at a nominal educational and non-profit rate through the official MOHO Clearinghouse website (https://moho.uic.edu). Clinicians and researchers wishing to use the instrument in clinical practice or research protocols must acquire an authorized manual. Digital reproductions, electronic health record (EHR) integrations, or translated versions require formal permission and licensing agreements from the UIC MOHO Clearinghouse.
12. References
The theoretical, psychometric, and clinical foundations of the COSA are established in the following peer-reviewed literature:
- Baron, K., Kielhofner, G., Iyenger, A., Goldhammer, V., & Wolenski, J. (2006). Child Occupational Self Assessment (COSA) (Version 2.2). Model of Human Occupation Clearinghouse, University of Illinois at Chicago.
- Keller, J., Kielhofner, G., & Forsyth, K. (2005). Developing the Child Occupational Self Assessment: A research and development project. British Journal of Occupational Therapy, 68(1), 12–20. https://doi.org/10.1177/030802260506800103
- Kielhofner, G. (2008). Model of Human Occupation: Theory and application (4th ed.). Lippincott Williams & Wilkins.
- Kramer, J. M., Kielhofner, G., & Smith, E. V., Jr. (2010). Validity evidence for using the Child Occupational Self Assessment (COSA) with children and youth with diverse abilities. American Journal of Occupational Therapy, 64(4), 621–632. https://doi.org/10.5014/ajot.2010.08129
- Kramer, J., Walker, R., Cohen, S. E., & Mermelstein, M. (2012). Creating collaborative partnerships: Using the Child Occupational Self Assessment (COSA) in school-based practice. Journal of Occupational Therapy, Schools, & Early Intervention, 5(3–4), 213–229. https://doi.org/10.1080/19411243.2012.744577
- Taylor, R. R. (2017). Kielhofner’s Model of Human Occupation: Theory and application (5th ed.). Wolters Kluwer.