Function Assessment Scale

Abstract

The Function Assessment Scale (FAS) is a brief, culturally grounded psychometric instrument developed by Bah et al. (2025) to measure functional status, adaptive functioning, and daily task performance among perinatal women in low-resource and post-crisis settings, specifically validated in Sierra Leone. Recognizing that standard psychiatric symptom checklists often fail to capture the real-world disability caused by maternal psychological distress, the instrument evaluates maternal capacity to execute essential daily tasks across domestic, personal, child-rearing, and social domains. Rooted in the qualitative and cross-cultural functional impairment assessment paradigms pioneered by Bolton and Tang (2002), the FAS emerged through a rigorous emic-etic development process involving qualitative task identification, linguistic translation and back-translation between English and Krio, and empirical item refinement. Starting from a 12-item preliminary draft, field testing and psychometric pruning reduced the instrument to a refined 5-item unidimensional measure: personal hygiene, meal preparation, domestic cleaning, childcare, and familial/community social engagement. The FAS uses a 4-point comparative rating format supported by culturally adapted visual aids (an illustration of an individual carrying graduated weights) where respondents compare their current functional difficulty to that of peers of similar age and life stage. Psychometric evaluation in the Western Area and Bombali districts of Sierra Leone established exceptional internal consistency reliability (Cronbach’s α = .920 for the final 5-item scale, increased from .890 after eliminating non-universal economic activities). This article provides a comprehensive psychometric review of the FAS, including its theoretical foundations, structural properties, cultural adaptation procedures, clinical and epidemiological utility in maternal health, and complete administration guidelines.

Keywords

Function Assessment Scale, Perinatal Mental Health, Functional Impairment, Maternal Health, Sierra Leone, Cross-Cultural Psychometrics, Adaptive Behavior, Global Mental Health, Psychosocial Functioning, Emic-Etic Methodology, Postpartum Depression, Daily Living Activities

Authors

The Function Assessment Scale was developed and validated by an international, multidisciplinary consortium of researchers specializing in global mental health, maternal-child health, and cross-cultural epidemiology:

• Abdulai Jawo Bah, PhD — Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom. (ORCID: 0000-0002-3334-7882; Correspondence: [email protected]).
• Haja Ramatulai Wurie, PhD — College of Medicine and Allied Health Sciences (COMAHS), University of Sierra Leone, Freetown, Sierra Leone.
• Mohamed Samai, MD, PhD — College of Medicine and Allied Health Sciences (COMAHS), University of Sierra Leone, Freetown, Sierra Leone.
• Rebecca Horn, PhD — Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom. (ORCID: 0000-0002-9869-544X).
• Alastair Ager, PhD — Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom. (ORCID: 0000-0002-9474-3563).

Purpose

The primary clinical and epidemiological purpose of the Function Assessment Scale (FAS) is to provide an ecologically valid, brief, and reliable metric of functional impairment among perinatal women—specifically pregnant women and mothers within their first postpartum year—living in resource-constrained, post-conflict, or global health settings. In psychiatric and psychological epidemiology, substantial controversy exists regarding the universal applicability of Western symptom-based diagnostic categories, such as those in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) or the International Classification of Diseases (ICD-11). In many low- and middle-income countries (LMICs), somatic complaints, existential exhaustion, or distress are framed in local idioms that do not map neatly onto Western criteria for major depressive episodes or generalized anxiety disorder.

However, functional impairment—defined as an individual’s subjective or observed inability to execute normative, expected daily tasks essential for personal survival, familial sustenance, and social cohesion—represents a universally acknowledged indicator of psychiatric morbidity and psychosocial disability. As articulated by global mental health researchers, measuring the direct functional consequences of psychological distress overcomes many biases inherent in Western-developed screening checklists. The FAS was intentionally engineered to serve three critical functions:

1. Clinical Screening and Triage: Identifying pregnant and postpartum women whose psychological suffering compromises their capacity to care for themselves, nurture their infants, manage their households, and maintain vital social ties, thereby prioritizing them for psychosocial interventions in primary healthcare and community outreach settings.
2. Outcome Evaluation: Supplying a responsive, quantifiable benchmark for maternal mental health interventions (such as group interpersonal psychotherapy, cognitive behavioral adaptations, or community health worker home visits) where restoration of functioning is frequently a more tangible, community-valued endpoint than symptom reduction alone.
3. Epidemiological Surveillance: Facilitating accurate estimation of disability burden associated with perinatal mental disorders within national health monitoring frameworks, such as the Sierra Leone Ministry of Health and Sanitation initiatives.

By shifting the assessment paradigm from abstract emotional self-reports to concrete daily functional behaviors, the FAS bridges the gap between biomedical diagnostics and community-defined priorities of maternal well-being.

Psychological Construct

The Function Assessment Scale measures the overarching psychological construct of functional status and adaptive behavior (APA Classification Code: 6200) tailored to the perinatal life stage. Within psychological measurement, functional status reflects the operational capability of an individual to fulfill normative social, occupational, domestic, and self-care roles within their specific sociocultural ecology. It does not measure distress itself, but rather the behavioral expression and physical manifestation of impairment resulting from psychological distress, physical illness, or psychosocial stress.

The FAS conceptualizes perinatal functional capacity across five foundational behavioral dimensions:

1. Personal Hygiene and Self-Care (Item 1)

Personal hygiene constitutes the most fundamental tier of adaptive behavior. In perinatal mental health, severe depressive states, apathy, and psychological distress manifest early as self-neglect, including failure to wash, groom, or attend to bodily postpartum recovery needs. In Sierra Leonean communities, the inability of a woman to maintain basic cleanliness is recognized as an acute warning sign of severe emotional collapse or spiritual alienation.

2. Domestic Nutritional Labor / Meal Preparation (Item 2)

Cooking and preparing meals for the household represent a central social and domestic role for women in West African households. Far from being a purely physical chore, meal preparation requires complex cognitive executive functioning, organization, sustained energy, and relational care. The loss of interest or energy required to source ingredients, maintain a cooking fire, and feed the family constitutes an immediate crisis for household food security and child nutrition.

3. Household Maintenance and Environmental Upkeep (Item 3)

Maintaining a clean living space encompasses sweeping, tidying, managing waste, and ensuring a hygienic home environment. In resource-limited rural and peri-urban environments, domestic cleaning is physically demanding and labor-intensive. Impairment in this domain indicates pervasive psychomotor slowing, physical fatigue, or profound lack of motivation associated with perinatal depressive and trauma-related conditions.

4. Direct Childcare and Nurturance (Item 4)

The capacity to care for children—both the newborn infant and older dependent offspring—is the behavioral cornerstone of perinatal maternal functioning. This dimension assesses responsive feeding, soothing, monitoring, and attending to the child’s developmental and safety needs. Disruptions in this domain carry serious developmental and physical consequences for the infant, including failure to thrive, malnutrition, impaired maternal-infant attachment, and elevated pediatric morbidity.

5. Familial and Community Social Connectivity (Item 5)

Social interactions with family and community members reflect social capital, relational integration, and the absence of depressive social withdrawal. In collectivist cultural contexts like Sierra Leone, functioning is fundamentally relational. An isolated perinatal woman who ceases greeting neighbors, visiting elders, or participating in community networks is experiencing profound psychosocial disruption. Re-establishing social interaction is both an indicator and an active mechanism of psychological recovery.

Theoretical Framework

The theoretical architecture of the Function Assessment Scale synthesizes three distinct psychometric and conceptual frameworks: the Emic-Etic Paradigm in Cross-Cultural Psychology, the Functional Impairment Model of Bolton and Tang, and the World Health Organization’s International Classification of Functioning, Disability and Health (ICF).

The Emic-Etic Paradigm

Cross-cultural mental health assessment is frequently undermined by “category fallacy,” wherein Western diagnostic constructs are uncritically imposed on non-Western populations without verifying their cultural relevance (an imposed *etic* approach). Conversely, a purely *emic* approach examines phenomena entirely through local concepts, idioms, and categories, occasionally sacrificing cross-population comparability. Bah et al. (2025) implemented a balanced emic-etic methodology. Qualitative free-listing and key informant interviews were deployed to capture local Krio and regional understandings of what a functional, healthy perinatal woman does each day. These indigenous behavioral markers were systematically harmonized with universal psychological concepts of disability, producing an instrument that is simultaneously culturally grounded and internationally interpretable.

Bolton and Tang’s Functional Impairment Framework

The structural methodology of the FAS directly derives from the seminal work of Bolton and Tang (2002), who developed standardized procedures for measuring functional impairment in low-income, humanitarian, and post-conflict societies (e.g., Uganda, Rwanda). Bolton and Tang demonstrated that in communities with low literacy and high exposure to collective trauma, asking participants directly about abstract intrapsychic symptoms (e.g., feelings of worthlessness, anhedonia) frequently produces measurement error or cultural misunderstandings. Instead, assessing an individual’s perceived difficulty in executing culturally expected, locally identified tasks serves as an accurate, stigma-reducing proxy for psychological disorder. The FAS explicitly operationalizes this framework by anchoring each item to concrete community tasks identified through iterative ethnographic inquiry.

The WHO ICF Model

At a global policy level, the FAS aligns with the WHO International Classification of Functioning, Disability and Health (ICF). The ICF model posits that disability is not an intrinsic biological deficit, but rather a dynamic interaction between a health condition (e.g., postpartum depression, obstetric trauma) and contextual environmental or personal factors. The FAS specifically assesses the “Activities and Participation” component of the ICF, evaluating functional limitations in domestic life, interpersonal interactions, and basic self-maintenance relative to the peer reference group.

Validity

The validation process for the Function Assessment Scale integrated qualitative, linguistic, and quantitative methodologies to confirm its appropriateness and structural integrity within the targeted sociocultural landscape of Sierra Leone.

Content and Face Validity

Content validity was established through preliminary qualitative investigations involving pregnant women, postpartum mothers, traditional birth attendants, and community healthcare workers across urban (Western Area) and rural/provincial (Bombali District) settings. A preliminary 12-item pool was generated reflecting daily tasks universally acknowledged as vital for maternal life. Through iterative expert panel reviews and community consultations, five items were eliminated due to cultural inappropriateness, regional irrelevance, or ambiguity, yielding a 7-item trial instrument.

Linguistic and Translation Validation

To ensure semantic equivalence, conceptual clarity, and cultural resonance, the scale underwent rigorous translation from English into Krio—the lingua franca of Sierra Leone—followed by blind back-translation into English by independent bilingual linguists. Cognitive interviewing was conducted with local perinatal women to verify that task descriptions and the response scaling were understood precisely as intended without cultural dissonance.

Empirical Item Refinement and Construct Purging

During field administration to perinatal cohorts in Western Area and Bombali, psychometric analysis revealed that the item assessing participation in income-generating activities exhibited severe structural distortion. In Sierra Leonean postpartum traditions, women frequently observe an initial rest or confinement period where direct economic work is proscribed or restricted by family support structures. Consequently, a vast majority of women reported zero or near-zero participation in commercial activities, which depressed the item mean and attenuated overall scale cohesion. Furthermore, general domestic chores required greater behavioral specificity. Researchers eliminated the commercial labor item and formally integrated meal preparation (cooking), yielding a streamlined, highly cohesive 5-item scale representing universal domestic and social adaptive demands.

Convergent and Concurrent Validation

Although the original paper primarily focused on validating the Sierra Leone Perinatal Psychological Distress Scale (SLPPDS), the FAS functioned as an integral concurrent validation criterion. Elevated functional impairment scores on the FAS demonstrated strong, statistically significant positive correlations with severe psychological distress, maternal anxiety, and depressive symptomatology, establishing substantial construct validity. Women meeting screening thresholds for psychological distress reported significantly greater difficulties in performing personal care, cooking, cleaning, childrearing, and social interaction.

Reliability

The Function Assessment Scale exhibits robust internal consistency reliability across perinatal populations in Sierra Leone. Reliability metrics documented across scale development iterations demonstrate excellent psychometric precision:

• Preliminary 7-Item Scale: In the initial testing cohort of pregnant and postpartum women, the 7-item iteration demonstrated a Cronbach’s alpha coefficient of α = .890, reflecting high homogeneity among task performance items.
• Final 5-Item Scale: Following the empirical removal of the non-universal economic labor item (“Engage in income-generating activities”) and the structural consolidation of daily domestic duties, the scale’s internal consistency improved markedly, achieving a Cronbach’s alpha of α = .920.

In psychometric measurement, an alpha coefficient exceeding .90 indicates excellent internal consistency, confirming that the 5 items tap into a unified underlying continuum of functional capacity. This high level of reliability is particularly noteworthy given the brevity of the scale; typical psychometric formulas (such as the Spearman-Brown prophecy formula) dictate that shortening a scale lowers its alpha coefficient, whereas the removal of noisy and culturally variable items in the FAS heightened measurement precision.

The standard error of measurement (SEM) is correspondingly minimized, allowing healthcare providers and clinical researchers to detect genuine shifts in functional capability over time without substantial confounding from measurement error.

Factor Analysis

While the original development study by Bah et al. (2025) focused its primary exploratory and confirmatory factor modeling on the multidimensional psychological distress scale (SLPPDS), the structural characteristics and inter-item correlation matrix of the 5-item FAS strongly support a robust unidimensional factor structure.

Methodologically, functional assessment scales designed under the Bolton and Tang tradition function as single-factor composite indices of overall disability. In exploratory assessments of the 5 items, the high internal consistency (α = .920) indicates that a single dominant general factor accounts for the vast majority of shared variance across:

1. Personal hygiene
2. Household meal preparation
3. Living space cleanliness
4. Childcare management
5. Social network engagement

Item-total correlations across the five items consistently exceed the standard psychometric threshold of .60, confirming that each task serves as a strong indicator of the latent functional status construct. The absence of multi-faceted task clustering justifies the computation of a single summative score representing overall perinatal functional impairment, eliminating the need for complex, cumbersome subscale calculations in field conditions.

Instrument / Measurement Tool

The Function Assessment Scale is an interviewer-administered or self-administered screening instrument designed specifically for rapid assessment in maternal health clinics, community healthcare posts, and epidemiological field surveys.

• Instrument Name: Function Assessment Scale (FAS)
• Target Population: Perinatal women aged 18 years and older (pregnant women and mothers with infants up to 12 months postpartum).
• Administration Format: Structured oral interview (ideal for low-literacy populations) or self-administered questionnaire.
• Item Count: 5 items.
• Completion Time: Approximately 2 to 4 minutes.
• Response Format: A 4-point Likert-type comparative difficulty scale. To bridge literacy barriers and standardize cross-subject comparisons, the rating options are visually supported by an illustrated cultural analog: a graphic depicting a man carrying progressively heavier physical weights, visually anchoring varying degrees of functional difficulty:
• 0 = No difficulty (Depicted with no weight / carrying nothing effortlessly)
• 1 = A little difficulty (Depicted carrying a light load)
• 2 = Moderate difficulty (Depicted carrying a medium, straining load)
• 3 = Extreme difficulty / Unable to do (Depicted carrying an overwhelming, crushing load)
• Comparative Frame of Reference: Respondents are explicitly instructed to rate their level of difficulty relative to other women of their same age, social background, and perinatal stage within their community, controlling for normal physical changes associated with pregnancy and early puerperium.
• Scoring Algorithm: Individual item scores are summed to generate a total Functional Impairment Score ranging from 0 to 15:
• 0 – 3: Minimal or no functional impairment (Normal perinatal adaptive functioning).
• 4 – 7: Mild functional impairment (Slight difficulty in demanding chores or social activities; monitor closely).
• 8 – 11: Moderate functional impairment (Substantial struggle across household, childcare, or self-care duties; candidate for psychosocial intervention).
• 12 – 15: Severe functional impairment (Critical breakdown of maternal daily functioning, immediate clinical triage and community support required).

Permissions & Fee and Test Year

The Function Assessment Scale was finalized and formally published in 2025 as part of the maternal mental health validation research conducted by Bah et al. The original research was published in the peer-reviewed journal Journal of Affective Disorders Reports under an open-access Creative Commons Attribution (CC-BY 4.0) license. Consequently, the FAS is an open-access, non-commercial public health instrument available free of charge for academic, clinical, governmental, and humanitarian research.

Users are permitted to copy, distribute, adapt, and translate the scale into other languages, provided appropriate attribution is rendered to the original authors (Bah et al., 2025) and the publication source is cited. Researchers planning to deploy the scale in new geopolitical contexts or languages are strongly encouraged to contact Dr. Abdulai Jawo Bah ([email protected]) and follow recommended cross-cultural adaptation guidelines to maintain ecological validity.

References

• Bah, A. J., Wurie, H. R., Samai, M., Horn, R., & Ager, A. (2025). Developing and validating the Sierra Leone perinatal psychological distress scale through an emic-etic approach. Journal of Affective Disorders Reports, 19, Article 100852. https://doi.org/10.1016/j.jadr.2024.100852
• Bolton, P., & Tang, A. M. (2002). An alternative approach to cross-cultural function assessment. Social Psychiatry and Psychiatric Epidemiology, 37(11), 537–543. https://doi.org/10.1007/s00127-002-0584-3
• Fisher, J., Cabral de Mello, M., Patel, V., Rahman, A., Tran, T., Holton, S., & Holmes, W. (2012). Prevalence and determinants of common perinatal mental disorders in women in low- and lower-middle-income countries: A systematic review. Bulletin of the World Health Organization, 90(2), 139–149G. https://doi.org/10.2471/BLT.11.091850
• Patel, V., & Kleinman, A. (2003). Poverty and common mental disorders in developing countries. Bulletin of the World Health Organization, 81(8), 609–615.
• World Health Organization. (2001). International Classification of Functioning, Disability and Health (ICF). World Health Organization. https://icd.who.int/

Items of the Scale