Measures of outcomes for children and youth

Measures of outcomes for children and youth

S46 TOOLS OF DISABILITY OUTCOMES RESEARCH Measures of Outcomes for Children and Youth Donald J. Lollar, EdD, Rune J. Simeonsson, PhD, MSPH, Upasana ...

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Measures of Outcomes for Children and Youth Donald J. Lollar, EdD, Rune J. Simeonsson, PhD, MSPH, Upasana Nanda, MPH ABSTRACT. Lollar DJ, Simeonsson RJ, Nanda U. Measures of outcomes for children and youth. Arch Phys Med Rehabil 2000;81 Suppl 2:S46-S52. Objective: To provide an overview of the issues related to the measurement of disability outcomes among children and on an assessment of selected instruments. Data Sources: Published scientific English literature in the area of child development, public health, and outcomes research. Study Selection: Studies selected were those that provide global measures of health outcomes focusing on children. Those selected allowed data collection to address the effects of intervention on individual children or populations of children. Psychometric characteristics were also a part of the selection process. Data Extraction: Specific guidelines for assessing the instruments include the number of scales and index capability, breadth of domains, inclusion of norms, capacity to measure elements of the World Health Organization model of functioning and disability, item and scaling bias, respondent burden, administrative burden, and retest reliability. Data Synthesis: Thirteen instruments were included. The measures vary in their utility for broad versus specific applications, eg, clinical and public health uses. Children themselves are often not part of the assessment process. In addition, environmental influences on health outcomes of children are not adequately addressed. Conclusion: Although it is challenging to evaluate outcomes associated with children with disabilities, there are frameworks and instruments that will advance outcome measurement. Approaches that include children should be explored further, and the environmental influences including and beyond the family require further measurement development. Key Words: Disabled children; Outcome assessment (health care); Rehabilitation. © 2000 by the American Congress of Rehabilitation Medicine

From the Disability and Health Branch, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA (Lollar); Frank Porter Graham Child Development Center, University of North Carolina, Chapel Hill, NC (Simeonsson); and Cardinal Glennon Children’s Hospital and Saint Louis University School of Public Health, St. Louis, MO (Nanda). Accepted in revised form August 18, 2000. Supported, in part, by the Robert Wood Johnson Foundation’s Promoting Excellence in End-of-Life-Care Program. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are associated. Presented in part at the conference Science of Disability Outcome Research, coordinated by the St. Louis University School of Public Health. Reprint requests to Donald J. Lollar, EdD, Disability and Health Branch, Div of Birth Defects, Child Development, and Disability and Health, Centers for Disease Control and Prevention, 4770 Bufford Hwy, F-34, Atlanta, GA 30341, e-mail: [email protected]. 0003-9993/00/8112-6304$3.00/0 doi:10.1053/apmr.2000.20624

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OCUMENTING OUTCOMES in children with chronic D health conditions and disabilities is a public health priority for several reasons. First, advances in medical care are contributing to survival of children with chronic health conditions who are at risk for secondary conditions. Second, treatment goals and health services for children need to focus on prevention of secondary conditions. Third, because children account for the highest prevalence of disabling conditions, we need to document and assess the outcomes associated with these health conditions.1 Traditional public health practice places disability in the same category as illness and injury—it is viewed as a negative health outcome to be prevented. Disability is usually associated with specific conditions, such as birth defects, spinal cord injury, or multiple sclerosis. Preventing a birth defect or serious injury prevents a disability. In this review article, we take a different approach: we view disability as a characteristic with which outcomes are associated. On this view, disability status defines an independent variable, demographic in character. In this article, we examine outcome measures in children with disabilities by (1) defining outcome measurement within the context of universal rights; (2) examining measurement issues unique to children using the World Health Organization’s (WHO) International Classification of Functioning and Disability (ICIDH-2) as a framework; (3) reviewing representative outcome measures; and (4) identifying implications for research and policy. Rehabilitation outcomes are usually framed by individual physical or psychosocial parameters. Defining and measuring outcomes related to health and disability in children and youth, however, need a broader base. These outcomes are best captured by broad principles of human rights. These principles were captured in the United Nations Convention on the Rights of the Child in 1959 and 1989. The declaration of rights includes: (1) preserving the dignity of children as people; (2) respecting the dignity of children as members of the community; (3) placing children first to receive protection, care, and assistance; (4) ensuring the right to a family environment and protecting families; and (5) considering cultural heritage. Children with disabilities are covered specifically by Article 23 of the UN Convention.2,3 It recommends that they should: (1) enjoy a full life, under conditions to ensure dignity, selfreliance, and participation; (2) have the right to special care and assistance for the child and caregivers; and (3) have assistance provided without cost for access to education, training, health care, and rehabilitation so to achieve social integration and individual development. These human rights principles and recommendations provide the backdrop from which our research should proceed and toward which our research efforts should lead. MEASUREMENT ISSUES AND CHALLENGES UNIQUE TO CHILDREN Measuring the health outcomes of children and youth with disabilities is important because public health and rehabilitation interventions are driven by analysis of appropriate outcomes at the community and clinical levels. Measuring costs and utilization of services are crucial components of health policy and practice. Evaluating related factors, ie, environmen-



tal barriers and facilitators, are also crucial to both public health and clinical rehabilitation. Although a large number of health status and health-related quality of life (HRQOL) instruments are available to measure health outcomes in the adult population, such measurement tools are limited for children and adolescents. Instruments to measure children’s health-related experiences are less well developed, and few tools have been designed that provide profiles or indexes of child health status. Instead, researchers and clinicians have focused on developing disease-specific measures for children.4 Assessing children’s health status and HRQOL compared with that of adults presents several challenges: (1) the greater dependency of the child’s health experiences on the family, (2) the developmental stage limitations of the child, and (3) proxy reporting by parent or primary caregiver.5,6 Physical growth from infancy through adolescence are paralleled by changes in behavioral, social, and psychologic development. Differentiating normal developmental variations from functional manifestations of disability constitutes an important measurement challenge. Proxy reporting raises the question of who should assess the child’s functional status and the reliability of that assessment. Proxy responses by parents and teachers correlate poorly with the perceptions of the child they represent.7 Hence, priority should be given to developing instruments that can be completed by children. At the same time, it must be recognized that children who are very young or have severe disabilities cannot participate fully in the assessment process parents, and, in those circumstances, parents and other primary caregivers are the best source of information. There are other challenges in measuring health status and outcomes of children and youth. Defining the chronicity of the characteristic to be measured as a health status or outcome indicator of disability should be a priority. In studies with adults, 6 to 12 months or more is often used as a criterion for chronicity or permanence of disability. The rapid nature of growth and development of children and the need to distinguish between transient delays and more permanent disability influence determination of the permanence or chronicity of disability. THE ICIDH-2 FRAMEWORK The goal of any classification is to delineate content and structure in order to organize the content. The International Classification of Diseases8 (ICD-10) classifies the causes and nature of disease and physical disorder. The Diagnostic and Statistical Manual of Mental Disorders9 (DSM-IV) classifies mental disorders. Diagnosis of a disease or disorder according to specified criteria is the basis for hierarchical and mutually exclusive classification in a multi-axial structure. Underlying

etiology and manifestations of physical and mental disorders have been included as entries in both the ICD-10 and DSM-IV classifications for children with disabilities and chronic conditions. Disability, however, is not an illness, disease, or disorder but a term describing a human condition characterized by limitations of function, performance, and adaptation in meeting environmental demands. Thus, although documentation of disability includes associated etiologic factors outlined in ICD-10 and DSM-IV, measurement of health outcomes should focus on the nature and extent of functional limitations in physical, social, and psychologic domains classified in ICIDH-2. Distinguishing the classification of etiologic and medical characteristics from consequences related to disability is important. The importance of distinguishing biologic aspects from functional manifestations is applicable to any outcome associated with consequences of disability. Growing awareness of the need for this distinction is evident in several conceptual models of disability that differentiate the underlying health conditions at the body, person, and societal level.10,11 In addition, 2 taxonomies have been produced, the International Classification of Impairments, Disabilities, and Handicaps12 and the Quebec classification.13 These models and classifications provide complementary perspectives on disability with key implications for measuring and documenting health status and outcome (table 1). First, the dimensional approach (including body, person, society) provides a logical and integrated basis for demonstrating the complexity of disability. Second, documenting manifestations across dimensions classifies functional characteristics rather than diagnoses or people. Documenting characteristics across dimensions has direct implications for identifying resources and supports for individuals or populations. Third, dimensional models are compatible with broader conceptualizations of accessibility, adaptation, and QOL.14 Disablement defines the process by which aspects of disability manifest themselves over time.15 This process has been most clearly outlined by WHO’s revised conceptual framework and classification scheme—the International Classification of Functioning and Disability (ICIDH2 B-2).16 It includes elements of body function, performance of personal activities, participation in societal situations, and environmental factors affecting each of the other elements, any of which can be viewed as health outcomes. For example, reduced respiratory function is an outcome at the body function level, termed impairment. Loss of ability to move oneself around is an outcome at the personal activity level, termed activity limitation. At each of these levels, the environment can either help or hinder the child. Medication can increase respiratory function, and a wheelchair can increase a child’s ability to move around. Disability outcomes, therefore, should identify both the dimen-

Table 1: Models and Classifications Defining a Dimensional Approach to Disability Dimensions of Disability Classification Model

Underlying Cause and Etiology

Limitations at Body Level

Limitations at Person Level

Limitations at Societal Level

Nagi/Institute of Medicine10 NCMRR11 ICIDH12 Quebec Classification13 ICIDH-216

Pathology Pathology Disease, injury Risk factors Health conditions

Impairment Impairment Impairment Organ systems Body functions and structures

Functional limitations Functional limitation Disability Capacities Activities

Disability Disability Handicap Life habits Participation


Societal limitations Environment Environment

Abbreviation: NCMRR, National Center for Medical Rehabilitation Research.

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sion assessment of environmental factors that facilitate or are hinder the outcome. Applying the concept to the models in table 1, disablement can be seen as a process with manifestations at different levels of body function and structure, activities and participation. Likewise, the environment influences or mediates functioning and adaptation. Using a dimensional approach in measuring health outcomes emphasizes that disability is multidimensional, and contributes to more precise linking of treatment to the intended areas of outcome. The dimensional approach enables clinicians and researchers to measure outcomes that cut across underlying health conditions and etiologies. The variability in manifestations is, then, a product of a person’s interactions with the environment over time.17 For example, problems of verbal articulation would be classified as impairments of body function and structure, problems of producing spoken messages would be limitations of activity performance, and problems of information exchange would be a restriction of participation. The provision of physical interventions and treatments and the role of assistive technology could be documented under the dimension of the environment, classified as either a barrier or a facilitator. It is useful to identify health status and outcome measures in children with chronic conditions and disabilities on the basis of the key dimensions they address. To that end, we use the dimensional approach (table 1) to review selected measures of health outcomes in children and to identify instruments on the basis of their content relative to the dimension of disablement covered. An instrument can be identified on the basis of content related to limitations at the body level, at the personal activity level, and at the social participation level. Content related to environmental factors is also identified. Instruments representing both surveillance and clinical instruments are also included in this review; but disease-specific instruments are not. Table 2 summarizes instruments based on dimension(s) reflected by instrument items. REVIEW OF REPRESENTATIVE MEASURES For this review, we include only global measures of health outcomes addressing children. These measures include various aspects of health experience and are used across various populations. They yield comprehensive information about the effect of treatments and interventions on individual children or populations that can be compared with similar populations. The measures are often multidimensional, encompassing health sta-

Table 2: Dimensions of Disability by Global Measures Measure


Limitations/ Body Level




Limitations/ Person Level

Limitations/ Society Level









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tus as well as social and psychologic functioning. Subjective dimensions of health experience are referred to as HRQOL measures. Global measures are likely to be robust because usually they have been subjected to long and systematic development and testing; therefore, more may be known about their measurement properties.18,19 Psychometric properties of the measures of health-related experience for children and adolescents reported in the literature is described below.5,20-25 Measures were selected based on the criteria outlined by Andresen et al.26 The report card (table 3) includes only those instruments on which substantial research of their psychometric properties has been conducted. Global measures can be viewed as health profiles. Health profiles are questionnaires that attempt to measure aspects of health-related experience, are designed to be applicable to patients in many health states, and are subdivided into a number of scale scores. Examples of these multiscale instruments include the Child Health Questionnaire (CHQ)27 ,the Rand Health Status Measure for Children (HSMC),28 and the Child Health and Illness Profile–Adolescent Edition (CHIP-AE).21 The principal advantage of using health profiles is to compare dimensions of disablement across different medical conditions to provide a picture of the health condition. Furthermore, the detail of health profiles allows for measurement of specific effects. One of the primary disadvantages to using the health profiles is that they may not measure areas of impairment that are characteristic of the condition being studied. Another limitation is that they may not detect small but clinically important changes in QOL for a specific condition.29 The selected measures will be identified and summarized. The report card will summarize their properties and usefulness. Rand Health Status Measure for Children The Rand study is the first published attempt to assess children’s health-related outcomes on a large scale.28 Based on a multidimensional model of child health, the HSMC is designed to evaluate 4 core domains, as well as general health perceptions and behavior problems.28 Two versions of the HSMC are available: one for children ages 0 to 4 years, and the other for children ages 5 to 13 years. This measure is administered to parents. A unique feature of this measure is that the scales for children were developed separately from those for adults, and equal attention was paid to developing both scales.30 Another strength is the usefulness of the profile scoring system for identifying specific areas of dysfunction.31 Other investigators have found the HSMC unable to differentiate between levels of dysfunction in pediatric populations and not sensitive enough to detect changes in children with chronic illness over time.24,32 Scales that might be useful for disability research include those that assess mobility, physical activity, self-care activity, and social relations. Three studies have evaluated the psychometric properties of the HSMC.28 Functional Status II-R The Functional Status II-R (FS II-R) provides a means of evaluating parents’ perceptions of the impact of illness on their children’s physical, social, and psychologic functions.24 It comprises 50 items, and certain item subsets apply only to children in certain age groups. It is suitable for children ages 0 to 16 years and takes approximately 30 minutes to complete. An item is scored as having an impact on functional status only if the parent states the problem results from the child’s current illness. Although the measure has good psychometric properties, it lacks specific assessment of mental health and disease-


OUTCOMES RESEARCH FOR CHILDREN, Lollar Table 3: Report Card for Outcomes Measures for Youth and Children Measures

Items, scales, summary and/ or index (total score) capability Breadth of HRQOL domains Norms, standards, values Measurement of ICIDH-2 model Item/scale/scaling bias Qualitative Quantitative Respondent burden Administrative burden Retest reliability Proxy reliability Discriminant validity Convergent validity Responsiveness Modes Accommodations






43 items, total index score

18 items, 6 domains

237 items, 3 domains

153 items, 6 domains, 20 subdomains

50 items, 14 domains






B⫹ B B A A A A B⫹ B B⫹

9 domains


B⫹ A A A A A A A B B⫹






B B⫹



Abbreviations: A, meets high standard; B, meets adequate standard; blank, inadequate information to judge.

and treatment-related symptoms. A 14-item version of the FS II-R also is available. A potential drawback of the FS II-R as a general health status measure is that health problems are not included in the score unless they are attributed by the parent to illness in the child. Another limitation of this tool is the interdependence among items. For example, some items are asked only if other items are answered in a particular manner, which may result in considerable missing or erroneous data. WeeFIM Instrument The WeeFIM® instrument, based on the format of the FIM™ instrument, was developed to measure and track development of functional independence in children with disabilities. It is designed for use with nondisabled children ages 6 months to 8 years, for children ages 6 months to 12 years who have developmental disabilities, and for people of all ages who have developmental disabilities or mental ages less than 7 years.33 It comprises 18 items involving 6 subscales: self-care, sphincter control, transfers, locomotion, communication, and social cognition. It is used either as an observational or an interview instrument and is usually conducted with someone (ie, parent, teacher) who is familiar with the child. The WeeFIM has been administered to different populations of children with developmental disabilities (eg, limb deficiencies, Down syndrome, motor impairments, spina bifida, prematurity).34-36 A series of studies has found that WeeFIM scores correlate with degree of neuromotor impairments, perceived current health status, and age, but not with a family’s socioeconomic status, child’s birth weight, or presence of neonatal complications.33,34,37,38 The WeeFIM also differentiates between children with and without disabilities, and WeeFIM scores correlate strongly.33,34,37,38 Pediatric Evaluation of Disability Inventory The Pediatric Evaluation of Disability Inventory (PEDI) was developed to document health status of chronically ill and disabled children from 6 months to 7.5 years in pediatric

rehabilitation settings. The inventory is designed to assess a child’s functional skills and behaviors; caregiver assistance of complex activities; and modification of environment for selfcare, mobility, and social function. It takes 45 to 60 minutes to administer and contains 197 questions, 20 caregiver assistance items, and 20 environmental modification items. The PEDI can be used as a parent report or structured interview instrument or by professionals observing the child’s functional behavior in a hospital, outpatient, or educational setting.39 A number of studies support the PEDI as a reliable and valid assessment of functional performance in children with disabilities.39-43 School Function Assessment The School Function Assessment (SFA) was developed to assess students’ abilities to function in the school setting. It is a noncategorical instrument assessing school tasks specifically, such as using classroom materials, as well as generalizable tasks, such as moving around or managing personal care. The instrument includes 3 sections—participation, measuring integration into 6 school environments; task supports, assessing assistance and adaptations to perform functional tasks; and activity performance, evaluating 18 person-level functions. Factor analysis of the instrument suggests 2 major components—a cognitive and behavioral function and a physical function.44 Child Health and Illness Profile–Adolescent Edition The CHIP-AE, developed by Starfield et al,21 is the first instrument that deals specifically with health assessment in adolescents. This instrument is a self-administered questionnaire for teens (ages, 11–17yr) and takes approximately 30 minutes to complete. Domains covered are: measures of comfort and discomfort; satisfaction with health, risk, disorder, achievement of social expectations in major role activities; and resilience.22 Each item is rated on a 5-point scale ranging from 0 (most healthy) to 4 (least healthy). The CHIP-AE has been used for children with chronic conditions. It detects differences in health states among age, gender, and socioeconomic status, Arch Phys Med Rehabil Vol 81, Suppl 2, December 2000



and may be useful in evaluating the impact of health care interventions on specific adolescent populations.22,45 Child Health Questionnaire The CHQ measures and compares the health of general and specific groups of children and estimates the benefits of alternative treatments.27,46 The 50-item parent-completed version of the CHQ includes 4 concepts designed to measure the emotional impact of the child’s health on the parent and family activities: the degree to which he/she feels limited in personal time due to the child’s health, the degree of limitations in family activities, and the overall cohesion of family relationships.27 There are 10 HRQOL concepts targeted at the child: physical functioning; bodily pain/discomfort; limitations in schoolwork and activities with friends due to physical health; general health perceptions; change in health; limitations in schoolwork and activities with friends due to emotional/behavioral difficulties; mental health; general behavior; and selfesteem. Three questionnaires have been developed, one for parents (CHQ-PF50) and their children aged 5 to 15 years (CHQ87), and the Parent Infant Toddler Health Questionnaire for infants ages 2 months to 5 years. The full-length 98- and 50-item version of the CHQ has been translated and fielded in French-speaking Canada, Germany, and the United Kingdom.47 The item-scaling results obtained in these pilot studies support the psychometric American/English properties of the CHQ-PF50 and its respective translations.47 Questionnaire for Identifying Children with Chronic Conditions The Questionnaire for Identifying Children with Chronic Conditions (QUICCC) was developed to identify children with chronic health conditions within a noncategorical framework.48 The conceptual framework for the measure focuses on the consequences of an underlying biologic, psychologic, or cognitive disorder. The measure comprises 39 question sequences that can be administered to a parent or guardian who is knowledgeable about the child’s health status and functional limitations. Items are distributed across 3 domains: 15 on functional limitations, 12 on compensatory dependency, and 12 on service use or need. An important feature of the QUICCC is that it yields information on all children in the family. A child is identified as having a chronic condition if any of 3 criteria are met: (1) a specified consequence of functional limitation, dependency on compensatory support, or service needs beyond routine care; (2) the consequence is attributable to an underlying biologic, psychologic, or cognitive condition; and (3) the condition has been experienced for 1 or more years. The measurement properties of the QUICCC have been examined in several studies.48,49 The validity of the QUICCC has been demonstrated in findings of classification accuracy and comparability with other measures of children’s health experience. Reliability on repeated assessment has revealed a kappa value of .73 and 88% agreement on meeting the definitional criteria.48 Stein and Silver49 have also demonstrated its utility to document childhood disability using the National Health Interview Survey Disability Supplement. POSNA Pediatric Musculoskeletal Functional Health Questionnaire The POSNA Pediatric Musculoskeletal Functional Health Questionnaire was developed by a work group of the Pediatric Orthopaedic Society of North America (POSNA) to measure outcomes of orthopedic interventions for children with musculoskeletal disorders.50 The POSNA comprises questions coverArch Phys Med Rehabil Vol 81, Suppl 2, December 2000

ing 3 major scales (global function and comfort; happy and satisfied; expectations). All scales provide scores that range from 0 to 100, with 100 representing the highest level of functioning. Internal consistency estimates range from .82 to .94 for questionnaires administered to parents and from .76 to .92 for those administered to children. Parallel test-retest values ranged from .71 to .97 and .76 to .96 for parents and children, respectively. In an interesting application to examine the role of proxy report, parent-child agreement values ranged from .45 to .87.50 ABILITIES Index The ABILITIES Index was developed as a practical instrument that practitioners and caregivers could use to document the nature and extent of childhood disability.51 The index encompasses 9 domains represented by the acronym ABILITIES (audition, behavior, intelligence, limbs, intentional communication, tonicity, integrity of health, eyes, structure). Within each domain, levels of functional status are operationally defined from normal (0) to extreme limitation (5). Ratings across the domains yield a profile of intra-individual differences. Ratings reflect relative rather than absolute patterns of functional status and encompass stable, enduring characteristics rather than developmental skills. The ABILITIES Index can provide a basis for describing an individual child or a population, as well as for personalizing interventions. The utility of the ABILITIES Index to document functional characteristics of childhood disability has been examined in various studies nationally and internationally.52 Interrater reliability has been studied53 in comparisons of ratings by parents, clinicians, and teachers of children with disabilities, yielding an average of 67% for exact agreement and 86.2% for agreement within 1 rating point. Analyses of agreement among members of interdisciplinary teams yielded weighted kappa coefficients ranging from .50 to .82, with a mean value of .67.54 Interrater agreement at this level has been characterized as moderate to substantial.55 A useful feature of the index has been its potential to identify subgroups of children on the basis of discrete profiles of functional characteristics. In an application with young children with various disabilities, hierarchical cluster analysis yielded a solution of distinct subgroups representing unique combinations of the nature and severity of functional limitations.51 This approach is consistent with Stein and Jessop’s recommendation24 for a noncategorical view of children. As an alternative to grouping on the basis of etiology or diagnosis, it may have utility in determining prevalence and eligibility on the basis of functional status. Gross Motor Function Measure The Gross Motor Function Measure (GMFM) is an 88-item instrument designed to measure 5 areas of motor function: (1) lying and rolling; (2) sitting; (3) crawling and kneeling; (4) standing; and (5) walking, running, and jumping.56 Each item is scored on a scale from 0 ⫽ does not initiate (0%) to 3 ⫽ completes the task (100%). Intermediate values are reflected by 1 ⫽ initiates (10% of the task) and 2 ⫽ (range, 10% ⬍ 100% of the task). Individual scale scores as well as an overall score can be obtained as a percentage value of gross motor function. A reliability study of 3 scales of the GMFM with children with cerebral palsy revealed interrater reliability values of .077 and .88 for 2 separate assessments.57 Youth Quality of Life Instrument–Research Version The Youth Quality of Life Instrument–Research version (YQOL-S) was developed to assess QOL among youth 12 to 18


years of age, including young people with physical and/or developmental disabilities.58 The instrument followed suggestions from a WHO report addressing the measurement of QOL among children.59 The instrument is youth-centered, uses a self-report from the young people wherever possible, is developmentally appropriate, allows cross-cultural comparisons, has both general and specific modules, and emphasizes positive health aspects rather than negative health characteristics and perceptions. After focus groups and interviews with youth, a conceptual model was generated, including 4 domains—(1) sense of self, (2) social relationships, (3) culture and community, and (4) general QOL. The instrument is divided into 2 sections: 27 descriptive items and 49 subjective items. Reliability and validity data indicate positive results for both psychometric characteristics.58 Quality of Well-Being Scale The Quality of Well-Being Scale (QWB)60 is a related instrument that summarizes health across symptoms, problems, and functional states (all preference-weighted) to provide a single score ranging from 0 (representing death) to 1 (representing symptom-free health). It is composed of 4 scales that focus on the physical impact of an illness related to symptoms, functions, social, and mobility levels. The QWB is a lengthy instrument requiring about 20 minutes to administer, and it uses a 6-day follow-back format wherein a parent reports on the child’s symptoms and functional level on each of the preceding 3 to 6 days (depending on the QWB version used). The QWB usually is given in person, sometimes using cue cards to aid subjects’ responses. Because of the need for a well-trained interviewer, the QWB is more complex to administer than other HRQOL measures.61,62 However, a recently introduced self-administered version of the QWB should make the instrument useful for more applications.63,64 Although the QWB has been used with adults and children, its applicability to children has been questioned because of its development on adult samples.31 Also, this measure is not recommended for use among children younger than 14 years because they may have difficulty remembering symptoms for the previous 6 days.20 Therefore, this measure may not be appropriate to use among children with disabilities. CONCLUSION Although measures of health-related status and outcome for children and youth are not as extensive as those for adults, the number and quality of such measures is increasing. Such measures tend to be multidimensional with varying degrees of coverage. The measures vary in terms of utility for broad versus specific applications. Even though some of the measures have demonstrated utility in clinical applications, further efforts are needed to develop efficient measures for use with broader applications. Important priorities in the development of new measures are identification of key indicators of child functioning and direct involvement of children in the assessment process. As used in this paper, the ICIDH-2 serves as a useful framework for differentiating measurement by dimensions of the disabling process. Such differentiation is important to achieve more sensitive measurement of health-related outcomes. The ICIDH-2 also provides promise of a taxonomy whereby such differentiation can be classified in terms of problems of body function or structure, limitations of personal activities, and restrictions of communal participation. Documentation of this kind is an essential component in evaluating needs and planning services at the level of the individual and the population.


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