Daily Living Skills Scale (DLSS)

Abstract

The Daily Living Skills Scale (DLSS) (Uljarević et al., 2023) is an open-source, comprehensive, informant-reported psychometric instrument designed to evaluate essential daily living skills (activities of daily living, ADLs) across a broad developmental, cognitive, and demographic continuum. Developed to address the prohibitive costs, licensing restrictions, and administration burdens associated with proprietary adaptive behavior assessments, the DLSS encompasses 53 items organized conceptually into three core domains: Self-Care, Homecare, and Community Participation. These subdomains comprehensively capture self-maintenance behaviors, including personal hygiene, grooming, dressing, toileting, meal preparation, housekeeping, domestic safety, healthcare management, financial transactions, and community navigation. Scale development adhered to the rigorous methodological guidelines of the Patient-Reported Outcomes Measurement Information System (PROMIS) framework, integrating systematic conceptual mapping, comprehensive literature reviews, and iterative feedback from clinician-scientists, individuals with neurodevelopmental disabilities, and family caregivers.

Psychometric evaluation in clinical and neurotypical samples aged 2 to 17 years demonstrated robust measurement properties. Confirmatory factor analysis (CFA) confirmed an overarching unidimensional latent construct representing global daily living skills (χ²-based model fit: Comparative Fit Index [CFI] = 0.953, Tucker-Lewis Index [TLI] = 0.951, Root Mean Square Error of Approximation [RMSEA] = 0.073 [90% CI: 0.071–0.074]). The instrument demonstrated exceptional model reliability (ω = 0.98) and total internal consistency (α = 0.97), with subscale internal consistencies ranging from α = 0.94 to α = 0.96. Item Response Theory (IRT) conditional reliability analyses established that the scale maintains high precision (reliability ≥ 0.80) across an exceptionally wide latent ability spectrum (θ = −4.2 to +2.4). Furthermore, multigroup invariance testing supported strict measurement invariance across age cohorts, sex, race, and ethnicity. Demonstrating strong convergent validity with established legacy measures such as the Vineland Adaptive Behavior Scales, Third Edition (VABS-3), the DLSS provides a clinically granular, equitable, and psychometrically robust measurement tool suitable for both developmental research and clinical practice.

Keywords

Adaptive Functioning, Autism Spectrum Disorder, Daily Living Skills, Activities of Daily Living, Neurodevelopmental Disabilities, Self-Care, Community Participation, Psychometrics, Item Response Theory, Measurement Invariance, Informant Report, PROMIS Framework

Authors

The Daily Living Skills Scale was conceptualized, developed, and empirically validated by an interdisciplinary team of clinical psychologists, psychiatrists, and psychometricians:

• Mirko Uljarević, M.D., Ph.D. — Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA, USA; School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia. (Corresponding author: [email protected]; ORCID: 0000-0002-3901-0814).
• Emily K. Spackman, Ph.D. — School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia. (ORCID: 0000-0003-2300-439X).
• Ru Ying Cai, Ph.D. — Aspect Research Centre for Autism Practice, Autism Spectrum Australia, Sydney, NSW, Australia. (ORCID: 0000-0002-3151-5401).
• Katherine J. Paszek, B.S. — Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA, USA.
• Antonio Y. Hardan, M.D. — Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, CA, USA. (ORCID: 0000-0002-4368-4509).
• Thomas W. Frazier, Ph.D. — Department of Psychology, John Carroll University, University Heights, OH, USA. (ORCID: 0000-0002-6951-2667).

Purpose

Daily living skills (DLS)—often conceptualized as the practical domain of adaptive behavior—represent the constellation of behaviors required for personal independence, autonomous living, and social inclusion within home and community settings. While cognitive abilities, executive functions, and structural language are critical determinants of neurodevelopmental trajectories, longitudinal investigations consistently reveal that adaptive functioning, specifically proficiency in daily living skills, is the primary driver of adult outcomes, employment success, community integration, and subjective quality of life in individuals with Autism Spectrum Disorder (ASD) and other neurodevelopmental disabilities (NDDs).

Historically, psychological research and clinical practice have relied almost exclusively on proprietary adaptive behavior instruments, such as the Vineland Adaptive Behavior Scales (VABS) and the Adaptive Behavior Assessment System (ABAS). Although psychometrically sound, these legacy instruments present significant structural and logistical impediments. They involve extensive assessment times, require expensive proprietary scoring software, impose restrictive test-purchasing licensing criteria, and frequently lack transparency regarding item calibration and item-level psychometrics. These barriers can constrain large-scale epidemiological studies, multinational translational research collaborations, and clinical monitoring in resource-limited or low- and middle-income healthcare settings.

To overcome these systemic bottlenecks, the Daily Living Skills Scale (DLSS) was designed as a completely open-source, standardized, informant-reported measure capable of providing deep behavioral granularity without commercial constraints. The primary clinical and empirical objectives of the DLSS include:

• Comprehensive Functional Phenotyping: Capturing the full spectrum of self-care, domestic maintenance, and community mobility behaviors across early childhood (ages 2–5), middle childhood (ages 6–12), and adolescence (ages 13–17).
• Longitudinal and Treatment Monitoring: Providing high conditional measurement precision across low, moderate, and high functional ranges to accurately capture developmental gains and therapeutic responses to behavioral, occupational, and pharmacological interventions.
• Cross-Diagnostic Utility: Demonstrating robust measurement invariance and structural validity across autistic youth, individuals with general neurodevelopmental conditions, and neurotypical peers, thereby facilitating comparative developmental investigations.
• Global Research Accessibility: Serving as an accessible, fee-free psychometric instrument that adheres strictly to contemporary open-science and FAIR (Findable, Accessible, Interoperable, and Reusable) data standards.

Psychological Construct

The DLSS operationalizes daily living skills within a hierarchically organized, multidimensional yet structurally coherent framework. While modern psychometric evaluations show that these behaviors load on a unified common factor representing overall practical functional capability, the instrument delineates three distinct conceptual subdomains that align with developmental milestones and clinical intervention targets:

1. Self-Care (28 Items)

The Self-Care subdomain encompasses behaviors essential for individual bodily maintenance, personal hygiene, and direct survival. These foundational behaviors represent early developmental acquisitions that typically emerge in toddlerhood and early childhood, progressing toward refined independence during school age. Content areas include:

• Personal Hygiene and Grooming: Independent execution of handwashing with soap, thorough tooth brushing, full-body bathing or showering, hair brushing or combing, and nail maintenance (e.g., Items 1, 2, 3, 6, 7).
• Toileting Independence: Complete management of biological elimination, appropriate use of sanitary paper, flushing mechanisms, and bodily hygiene post-elimination (e.g., Items 4, 5).
• Dressing and Undressing: Selecting contextual, weather-appropriate attire, orienting garments correctly (front-to-back, right-side out), operating fasteners (zippers, snaps, buttons), putting on and tying footwear, and undressing appropriately based on social context (e.g., Items 8, 9, 10, 11, 12).
• Feeding and Ingestion: Safe chewing and deglutition, spill-free drinking from open cups, proficient utilization of dining utensils (fork, knife, spoon), serving food from common vessels, and manipulating complex commercial food packaging (e.g., Items 13, 14, 15, 16, 17).

2. Homecare (10 Items)

The Homecare subdomain evaluates instrumental domestic behaviors required to maintain a safe, functional, and sanitary private living space. These skills involve complex sequencing, multi-step executive planning, and domestic safety vigilance. Content areas include:

• Culinary Preparation and Kitchen Maintenance: Preparing basic cold snacks and independent simple hot meals (e.g., utilizing a microwave or range), adhering strictly to kitchen safety protocols such as turning off heat-producing appliances, clearing dirty dishware, washing dishes, and organizing clean utensils (e.g., Items 18, 19, 20, 21, 22, 23).
• Environmental Sanitation and Household Organization: Wiping down surfaces, mopping or vacuuming floors, taking out refuse and recyclables, organizing personal belongings, and making one’s bed (e.g., Items 24, 25, 26, 27, 28, 32).
• Clothing Maintenance: Categorizing dirty garments, operating laundry appliances (washing machines and dryers), and neatly folding and storing clean apparel (e.g., Items 29, 30, 31).
• Domestic Safety and Health Management: Locking and unlocking perimeter entryways, identifying and mitigating common domestic hazards (e.g., sharp implements, thermal burns), knowing emergency responses (fire protocols, contacting emergency services), adhering to scheduled medical regimens, accurately articulating pain or somatic symptoms, and addressing minor injuries with basic first aid (e.g., Items 33, 34, 35, 36, 37, 38).

3. Community Participation (15 Items)

The Community Participation subdomain reflects higher-order practical adaptation, evaluating an individual’s autonomous functioning outside the home environment. These behaviors require social competence, navigational independence, economic understanding, and adaptive problem-solving within dynamic public environments. Content areas include:

• Pedestrian Safety and Independent Navigation: Adhering to pedestrian traffic signals, safely traversing roadways, navigating neighborhood routes, and independently boarding and riding public transit networks (e.g., Items 41, 42, 43, 51).
• Economic Competence: Comprehending currency values, executing monetary transactions, managing change, and regulating discretionary personal funds or basic budgets (e.g., Items 44, 45, 46).
• Communication and Scheduling: Utilizing personal communication devices (smartphones, landlines) to exchange essential information, managing personal calendars, scheduling appointments, and comprehending public instructional signage (e.g., Items 39, 49, 50).
• Public Safety and Self-Advocacy: Maintaining physical possession and security of identification documents, observing stranger safety guidelines, adhering to expected behavioral norms in public settings, and independently advocating for personal accommodations or assistance in complex community environments (e.g., Items 40, 47, 48, 52, 53).

Theoretical Framework

The conceptual architecture and operationalization of the DLSS are anchored in several foundational psychometric, psychological, and developmental paradigms:

The AAIDD Multidimensional Model of Adaptive Behavior

The DLSS aligns directly with the theoretical framework established by the American Association on Intellectual and Developmental Disabilities (AAIDD). Under the AAIDD model, human functioning represents an ecological dynamic resulting from the interaction between individual competencies and environmental demands. Adaptive behavior is formally defined as the collection of conceptual, social, and practical skills learned and performed by individuals in their everyday lives. The DLSS focuses extensively on the practical skill domain, translating broad theoretical tenets into discrete, observable, and measurable functional tasks spanning personal autonomy, instrumental daily activities, and community self-direction.

The PROMIS Instrument Development Methodology

The empirical construction of the DLSS was systematically guided by the standards established by the Patient-Reported Outcomes Measurement Information System (PROMIS). The PROMIS paradigm mandates rigorous, iterative instrument development stages:

1. Exhaustive Conceptual Mapping: Deconstructing the broad construct of daily living skills into observable behavioral sub-elements via systematic reviews of existing scales and developmental milestone literature.
2. Item Generation and Harmonization: Formulating an expansive preliminary item bank characterized by clear, unambiguous syntax, eliminating dual-barreled statements, and minimizing cultural or socioeconomic biases.
3. Stakeholder and Expert Cognitive Vetting: Reviewing potential items with neurodevelopmental clinician-scientists, clinical neuropsychologists, and caregiver/individual stakeholders to maximize content validity and face validity.
4. Advanced Psychometric Calibration: Utilizing combined Classical Test Theory (CTT) and Modern Item Response Theory (IRT) methodologies to ensure exceptional measurement precision across all ability levels.

Developmental Systems Theory and the ICF Framework

The scale integrates the International Classification of Functioning, Disability and Health (ICF) promulgated by the World Health Organization (WHO). The ICF differentiates between bodily impairments (e.g., neurological deficits), activity limitations (e.g., inability to self-feed), and participation restrictions (e.g., inability to engage in community activities). By focusing on functional execution rather than physiological or cognitive capacity alone, the DLSS assesses the intersection of an individual’s underlying developmental capabilities and their real-world participation across naturalistic home and societal environments.

Validity

The psychometric validation of the DLSS (Uljarević et al., 2023) involved comprehensive empirical evaluations of construct, convergent, discriminant, and structural validity across clinically characterized and general population samples.

Convergent Validity

Convergent validity was examined against gold-standard, clinically established adaptive behavior inventories, primarily the Vineland Adaptive Behavior Scales, Third Edition (VABS-3). The DLSS Total Score exhibited exceptionally strong, statistically significant positive correlations with the VABS-3 Daily Living Skills Domain raw scores (r > 0.85, p < .001). Furthermore, targeted conceptual domain-to-domain comparisons confirmed convergent validity:

• The DLSS Self-Care subscale correlated strongly with the VABS-3 Personal subscale.
• The DLSS Homecare subscale exhibited high concordance with the VABS-3 Domestic subscale.
• The DLSS Community Participation subscale demonstrated robust positive associations with the VABS-3 Community subscale.

Discriminant and Criterion Validity

The instrument demonstrated expected patterns of discriminant and criterion-related validity. When examining diagnostic group differences, the DLSS total score exhibited a moderate, statistically significant negative correlation with an Autism Spectrum Disorder (ASD) diagnosis (reflecting the well-documented functional independence discrepancies common in clinical neurodevelopmental populations relative to neurotypical peers). Discriminant validity was demonstrated by observing lower, moderate associations with psychiatric symptoms that do not directly assess functional capability (e.g., anxiety, internalizing behaviors). Conversely, constructs mechanistically linked to adaptive behavioral execution—such as executive functioning (working memory, cognitive flexibility, behavioral inhibition) and motor coordination—exhibited stronger correlations with DLSS scores, aligning with neuropsychological models of functional independence.

Reliability

The DLSS demonstrates excellent measurement precision across diverse psychometric reliability metrics, satisfying both Classical Test Theory and Modern Psychometric/IRT criteria.

Internal Consistency and Model-Based Reliability

Classical internal consistency coefficients for the DLSS are exceptionally high across all operational levels:

• Total DLSS Scale: Cronbach’s α = 0.97.
• Self-Care Subdomain: Cronbach’s α = 0.96.
• Homecare Subdomain: Cronbach’s α = 0.94.
• Community Participation Subdomain: Cronbach’s α = 0.94.

Because traditional coefficient alpha can be influenced by scale length and correlated residual variances, modern model-based composite reliability was formally estimated. The primary general Daily Living Skills factor demonstrated a model reliability coefficient of ω = 0.98, indicating that the vast majority of observed variance reflects true construct variance.

Conditional Reliability (Item Response Theory)

A critical advantage of the DLSS over legacy instruments is its documented conditional reliability derived from IRT models. Rather than assuming that measurement precision is uniform across the entire continuum of ability, IRT allows for the evaluation of the scale information function across the latent trait spectrum (θ). The DLSS total scale achieves a conditional reliability of ≥ 0.80 across an expansive continuum ranging from θ = −4.2 (reflecting severe functional impairment) to θ = +2.4 (reflecting advanced functional independence). This dynamic range minimizes both floor and ceiling effects across early childhood through late adolescence.

Factor Analysis

The latent structural integrity of the DLSS was evaluated using rigorous latent variable modeling, confirmatory factor analysis (CFA), and structural equation modeling (SEM).

Confirmatory Factor Analysis (CFA)

A primary unidimensional CFA model evaluating all 53 items loading onto a single general Daily Living Skills latent factor revealed an excellent fit to the empirical data:

• Comparative Fit Index (CFI): 0.953
• Tucker-Lewis Index (TLI): 0.951
• Root Mean Square Error of Approximation (RMSEA): 0.073 (90% Confidence Interval: 0.071 – 0.074)

All 53 items yielded high, statistically significant standardized factor loadings (λ generally > 0.65 to 0.90) onto the primary general factor. Concurrently, bifactor modeling and multidimensional conceptual models supported the extraction and computation of the three clinically relevant subscales—Self-Care (28 items), Homecare (10 items), and Community Participation (15 items)—confirming that while specific domain subscores provide diagnostic granularity, an overarching general adaptive factor explains common variance.

Measurement Invariance

To establish that the DLSS measures the same underlying construct equivalently across diverse demographic cohorts, multigroup confirmatory factor analytic measurement invariance was formally evaluated. The unidimensional structure demonstrated robust evidence of:

• Configural Invariance: Equivalent latent factor structure across groups.
• Metric (Weak) Invariance: Equivalent factor loadings across groups.
• Scalar (Strong) Invariance: Equivalent item response thresholds/intercepts across groups.
• Residual (Strict) Invariance: Equivalent item unique variances across groups.

Strict measurement invariance was fully supported across biological sex (male vs. female), chronological age brackets, race, and ethnicity. These invariance properties confirm that differences in DLSS observed scores reflect true differences in adaptive capacity rather than measurement bias.

Instrument / Measurement Tool

• Instrument Name: Daily Living Skills Scale (DLSS)
• Test Type: Standardized Informant-Report Questionnaire / Clinical Rating Scale
• Administration Format: Paper-and-pencil questionnaire or secure digital electronic administration (e.g., REDCap, Qualtrics)
• Target Population: Children and adolescents aged 2 to 17 years across neurodevelopmental conditions (autism spectrum disorder, ADHD, intellectual disability) and neurotypical development
• Informant: Parent, legal guardian, or primary caregiver with extensive naturalistic observation of the child
• Number of Items: 53 items
• Subdomains & Content Breakdown:
  • Self-Care Subscale: 28 items (Items 1–17, 34, 36–38, plus personal grooming/dressing)
  • Homecare Subscale: 10 items (Items 18–33, 35)
  • Community Participation Subscale: 15 items (Items 39–53)
• Authentic Response Scale: 3-point scale measuring the degree of independent performance:
  • 0 = Does not perform
  • 1 = Performs with assistance/prompting
  • 2 = Performs independently (or equivalent rating scale measuring degree of independence)
• Scoring Rules:
  • Item scores are non-reversed.
  • Subscale raw scores are derived by summing the items corresponding to each respective domain (Self-Care, Homecare, Community Participation).
  • The Total DLSS score is calculated by summing all 53 items (Range: 0 to 106).
  • Higher numerical scores reflect greater functional autonomy and independent execution of daily living skills.
• Estimated Completion Time: Approximately 10 to 15 minutes

Permissions & Fee and Test Year

• Year of Initial Publication: 2023
• Commercial Status: Non-commercial, open-source instrument
• Assessment Fee: No fee (Free for academic research, epidemiological studies, and clinical care)
• Licensing and Permissions: Published under the terms of the Creative Commons Attribution License (CC BY 4.0), permitting unrestricted use, distribution, and reproduction in any medium provided the original authors and source publication are properly cited.
• Correspondence & Access Inquiries: Dr. Mirko Uljarević ([email protected]), Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine.

References

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• Uljarević, M., Spackman, E. K., Cai, R. Y., Paszek, K. J., Hardan, A. Y., & Frazier, T. W. (2023). Daily living skills scale: Development and preliminary validation of a new, open-source assessment of daily living skills. Frontiers in Psychiatry, 13, Article 1108471. https://doi.org/10.3389/fpsyt.2022.1108471
• World Health Organization. (2007). International Classification of Functioning, Disability and Health: Children & Youth Version (ICF-CY). World Health Organization. https://apps.who.int/iris/handle/10665/43737

13. Items of the Scale (Questionnaire)