1. Abstract
The Function Assessment Scale (Bah et al., 2025) is an ecologically and culturally grounded psychometric instrument specifically engineered to assess functional impairment and daily task execution among perinatal women, including pregnant women and new mothers, within resource-constrained and post-conflict environments such as Sierra Leone. Developed through an integrated emic-etic methodology adapted from the classic qualitative-to-quantitative ethnographic paradigm pioneered by Bolton and Tang (2002), the scale captures the behavioral manifestations of perinatal mental health difficulties across primary domestic, economic, familial, and social domains. Initially drafted as a 12-item pool exploring everyday tasks undertaken for self, family, and community, the instrument underwent rigorous cultural adaptation, linguistic validation, forward- and back-translation between English and Krio, item reduction, and pilot testing in the Western Area and Bombali districts. Following the removal of culturally incongruent tasks and the empirical integration of essential maternal routines, the definitive instrument emerged as a core 5-item rating scale, with a recommended 4-item unidimensional variant optimized for statistical consistency.
Items are rated on an anchored 5-point Likert-type severity continuum ranging from 0 (“None / No difficulty”) to 4 (“Often cannot do the task”), visually supported by culturally tailored pictorial anchors depicting a person carrying escalating physical burdens. Psychometric evaluations demonstrate strong internal consistency, yielding an initial Cronbach’s alpha of 0.890 for the general instrument, which improves to 0.920 upon the removal of the income-generation task due to structural variance in formal economic participation among women in the target demographic. As both an outcome measure and an epidemiological screening tool, the Function Assessment Scale provides global mental health researchers, midwives, and public health clinicians with an objective, locally validated metric that bridges maternal psychological distress and real-world behavioral disability.
2. Keywords
Function Assessment Scale, Perinatal Functional Impairment, Maternal Mental Health, Sierra Leone, Emic-Etic Methodology, Daily Living Activities, Postpartum Depression, Low- and Middle-Income Countries, Cross-Cultural Psychometrics, Bolton and Tang Approach, Psychometric Validation, Global Health.
3. Authors
The Function Assessment Scale was designed, culturally operationalized, and psychometrically evaluated by a multidisciplinary team of global public health researchers, psychiatrists, and health systems scholars based in Sierra Leone and the United Kingdom:
- Abdulai Jawo Bah — Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom. (ORCID: 0000-0002-3334-7882; Email: [email protected]).
- Haja Ramatulai Wurie — College of Medicine and Allied Health Sciences (COMAHS), University of Sierra Leone, Freetown, Sierra Leone.
- Mohamed Samai — College of Medicine and Allied Health Sciences (COMAHS), University of Sierra Leone, Freetown, Sierra Leone.
- Rebecca Horn — Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom. (ORCID: 0000-0002-9869-544X).
- Alastair Ager — Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom. (ORCID: 0000-0002-9474-3563).
4. Purpose
The primary clinical and epidemiological purpose of the Function Assessment Scale is to systematically measure, quantify, and track perinatal women’s subjective difficulty in performing vital, culturally expected daily living tasks across the pregnancy and postpartum trajectories. While standard diagnostic instruments derived from high-income countries predominantly focus on intrapsychic, affective, and cognitive symptoms—such as dysphoria, anhedonia, somatic anxiety, or suicidal ideation—global health practitioners frequently face the dilemma of cross-cultural symptom validity. In many low- and middle-income country (LMIC) settings, mental health problems are not conceptualized through Western diagnostic categories like Major Depressive Disorder or Generalized Anxiety Disorder, but are instead recognized and articulated through functional disability, role impairment, and an inability to execute critical familial and domestic duties.
From an applied clinical perspective, functional status assessment serves as a vital diagnostic proxy and complement to psychiatric symptom inventories. A pregnant woman or new mother may experience profound emotional distress, yet intervention is frequently prompted only when that internal distress impedes her ability to sustain herself, her infant, and her household. The Function Assessment Scale provides primary healthcare workers, community health officers, and maternal-child health aides with a standardized, non-stigmatizing screening mechanism that evaluates the behavioral consequences of perinatal psychological distress. By contextualizing mental suffering in the tangible framework of day-to-day productivity and role performance, health systems can rapidly triage women who require clinical, psychological, or social welfare support.
From an epidemiological and programmatic vantage point, the tool functions as an essential outcome indicator for public health interventions in maternal health. In humanitarian, post-conflict, and resource-limited settings, mental health and psychosocial support (MHPSS) programs require validated indices to determine whether community-based interventions, cash-transfer programs, or clinical care lead to measurable recoveries in social and occupational functioning. Traditional Western disability measures, such as the World Health Organization Disability Assessment Schedule (WHODAS 2.0), often contain items that assume access to modern infrastructure (e.g., automated appliances, formal corporate employment, paved walkways), rendering them structurally invalid or difficult to contextualize in agrarian or informal urban settings. The Function Assessment Scale resolves this discrepancy by grounding every item within the verified, empirical realities of West African maternal life.
5. Psychological Construct
The underlying construct operationalized by the instrument is perinatal functional impairment, situated within the broader biopsychosocial domain of activities of daily living (ADLs) and instrumental activities of daily living (IADLs) specific to motherhood in low-resource environments. Functional impairment is defined as the self-reported subjective degree of difficulty, hindrance, or absolute inability experienced by an individual when attempting to execute tasks necessary for personal subsistence, household maintenance, economic survival, and community membership. The construct does not merely measure physical capacity; rather, it reflects the interaction between physical health, psychological vitality, emotional equilibrium, and social obligations.
The instrument operationalizes this construct across four key functional sub-domains:
- Domestic and Maintenance Labor: Represented by item 1 (“Doing household chores (e.g., cleaning the house, washing clothes, fetching water)”). In the target sociocultural setting, domestic labor requires immense physical exertion, resilience, and executive functioning. Tasks such as drawing water from wells or rivers and manual laundry are foundational to household hygiene. Functional failure in this domain reflects pronounced somatic and psychological exhaustion.
- Nutritional Care and Subsistence: Represented by item 2 (“Cooking / preparing food”). Food preparation is a central maternal and familial responsibility within West African domestic architecture. The psychological will and physical stamina to gather firewood, process raw ingredients, and prepare daily meals directly affect the nutritional security of existing children and the household, serving as a direct marker of severe maternal functional decline when impaired.
- Economic and Livelihood Engagement: Represented by item 3 (“Engage in income-generating activities (e.g., petty trading, farming, selling)”). While vital for independent financial resilience, empirical findings by Bah et al. (2025) identified that this domain exhibits high contextual variance, as societal expectations, seasonal changes, physiological stages of late pregnancy, and household wealth dictate whether a perinatal woman can or must engage in economic enterprise.
- Interpersonal, Caregiving, and Social Functioning: Encompassed in item 4 (“Taking care of children and family members”) and item 5 (“Participating in community activities / social events”). These items capture maternal relational functioning and communal integration. The inability to care for dependents or engage in vital life-cycle rituals (such as child naming ceremonies, weddings, and mutual aid groups) marks profound social withdrawal, a hallmark of severe perinatal depressive and anxiety states.
6. Theoretical Framework
The architecture of the Function Assessment Scale is anchored in the theoretical integration of two major frameworks: the Emic-Etic Paradigm of Cross-Cultural Psychometrics articulated by Bolton and Tang (2002), and the Biopsychosocial Model of Disability codified by the International Classification of Functioning, Disability and Health (ICF).
Cross-cultural psychiatry has long grappled with the conceptual tension between universal (etic) categories of psychopathology and culture-bound, locally defined (emic) expressions of illness. Bolton and Tang demonstrated that rather than imposing Western psychiatric constructs via direct translation of existing instruments, valid global psychometrics require qualitative ethnographic preliminary studies. Through free-listing, key informant interviews, and focus groups, researchers identify local tasks considered normative and essential by the population itself. The theoretical rationale posits that while the internal psychological manifestations of mental illness may vary, severe psychiatric distress consistently degrades an individual’s capacity to perform tasks that their specific culture considers imperative for survival and social cohesion. By asking respondents to judge their current capacity against local normative standards (“compared to other perinatal women of their age”), the scale neutralizes baseline cultural expectations and isolates the idiosyncratic variance attributable to illness.
Simultaneously, the scale adheres to the WHO ICF theoretical model, which conceptualizes disability not as an intrinsic individual biological defect, but as an emergent property of the dynamic interaction between health conditions (such as perinatal depression, anemia, or obstetric trauma) and environmental, contextual, and personal factors. In resource-poor settings, physical and mental states interact synergistically: perinatal psychological distress induces vegetative symptoms (lethargy, psychomotor retardation, sleep disturbance) which, when combined with arduous physical tasks (e.g., carrying 20-liter water containers), precipitates functional collapse. The Function Assessment Scale operates precisely at this interface, measuring the behavioral downstream impact of distress upon contextual daily execution.
7. Validity
The scale’s validation process involved meticulous qualitative and quantitative steps conducted across diverse epidemiological zones in Sierra Leone, specifically including urban and peri-urban populations in the Western Area (Freetown and surrounding informal settlements) and agrarian rural populations in Bombali District:
- Content and Face Validity: The initial scale pool was derived from qualitative ethnographic free-listing exercises inquiring about the universe of activities undertaken by pregnant women and new mothers for themselves, their households, and their communities. An initial 12-item inventory was critically reviewed by local clinical and sociocultural experts. Five items were purged due to cultural inappropriateness, structural irrelevance, or because they did not constitute daily recurring routines. The critical task of “cooking / preparing food” was inductively added following field observations, securing robust face and content validity that accurately maps the perinatal workload in West Africa.
- Linguistic and Translation Validity: To eliminate semantic distortion, all items underwent forward translation from English into Krio by independent bilingual native speakers, followed by blind back-translation into English. Discrepancies were arbitrated by expert consensus panels involving maternal health workers and cultural linguists, establishing that the idiomatic meaning of effort, burden, and domestic task execution remained unaltered.
- Ecological and Construct Validity: The scale incorporates a culturally adapted comparative cognitive frame: respondents evaluate their functional capacity relative to their demographic peers (“compared to other perinatal women of their age”). This design controls for systemic, environmental, and infrastructure-related structural barriers that affect all women equally (e.g., water scarcity in the dry season), ensuring that observed deficits capture individual functional impairment rather than collective structural deprivation.
- Item Divergence and Economic Variance: Empirical psychometric testing revealed that Item 3 (“Engage in income-generating activities”) behaved differently from the remaining domestic and caregiving items. Because a substantial subset of women in the sample did not routinely engage in petty trading or agricultural sales due to extreme poverty, advanced gestational age, or restrictive family structures, this item demonstrated lower correlation with the general domestic functioning latent factor. This quantitative divergence empirically validated the distinct theoretical nature of formal livelihood activities compared to universal domestic labor.
8. Reliability
The psychometric reliability of the Function Assessment Scale was evaluated through rigorous classical test theory metrics, focusing on internal consistency within perinatal cohorts in Sierra Leone:
In the initial developmental cohort, an unrefined 7-item version yielded a high Cronbach’s alpha of 0.890, establishing that the aggregated items tapped a cohesive, interconnected construct of daily functioning. Subsequent refinement during scale reduction demonstrated that the internal consistency was significantly influenced by the composition of the economic activity item. Specifically, item-total deletion analyses revealed that removing Item 3 (“Engage in income-generating activities (e.g., petty trading, farming, selling)”) produced a dramatic increase in internal consistency, elevating the Cronbach’s alpha to 0.920.
This high alpha coefficient (α = 0.920) indicates exceptional item inter-relatedness and exceptionally low measurement error, surpassing the standard academic benchmark of 0.80 for psychological research and meeting the strict threshold of 0.90 required for high-stakes individual clinical decision-making. The high reliability of the 4-item optimized variant reflects the universal shared variance of the core domestic tasks: a woman struggling to wash clothes or clean the home is overwhelmingly likely to experience parallel severe difficulties in food preparation, child care, and participation in community gatherings.
9. Factor Analysis
Although formal structural equation modeling and confirmatory factor analysis (CFA) fit indices were not reported in the foundational baseline validation paper by Bah et al. (2025), the empirical item analysis and psychometric behavior strongly corroborate a unidimensional factor structure for the primary domestic, caregiving, and social tasks. The item-total correlations and inter-item correlation matrices demonstrate that household maintenance, nutritional preparation, dependent caregiving, and community interaction load heavily onto a single underlying latent variable representing Global Perinatal Functional Capacity.
The statistical behavior of Item 3 (“Engage in income-generating activities”) indicates a bifactor or two-tier conceptual structure in contexts where economic tasks are retained. While domestic and caregiving tasks are universally normative across all reproductive households in Sierra Leone, participation in the cash economy or agrarian market labor is moderated by external socioeconomic determinants, seasonal agricultural cycles, household wealth, and spousal support. Consequently, when Item 3 is retained within a single-factor extraction, it exhibits lower item-total correlation and inflates residual variance, pulling Cronbach’s alpha down to 0.890. Conversely, constraining the instrument to universal domestic and communal behaviors isolates a pristine, highly saturated unidimensional factor, accounting for the elevation of internal consistency to 0.920. Future validation studies utilizing large-sample Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) are indicated to report formal factor loadings, Root Mean Square Error of Approximation (RMSEA), Comparative Fit Index (CFI), and Tucker-Lewis Index (TLI) metrics across diverse geopolitical settings.
10. Instrument / Measurement Tool
- Instrument Name: The Function Assessment Scale (alternate name: Function Scale).
- Authors: Abdulai Jawo Bah, Haja Ramatulai Wurie, Mohamed Samai, Rebecca Horn, and Alastair Ager.
- Publication Year: 2025.
- Target Population: Adult perinatal women (pregnant women and new mothers aged 18 years and older).
- Administration Format: Structured interviewer-administered rating scale; items are read aloud to the respondent to accommodate varying literacy levels.
- Cognitive Anchor / Framing: Respondents are explicitly instructed to consider each daily task read aloud and rate the difficulty experienced in performing it relative to other perinatal women of their age within their community.
- Item Count: 5 items in the full operational version; 4 items in the psychometrically optimized domestic unidimensional version (excluding item 3).
- Visual Aid: The scale is administered using a standardized visual four-to-five-point anchor depicting an illustration of a human figure carrying increasing degrees of physical weight, bridging conceptual abstraction and low literacy.
- Authentic Response Scale:
- 0 = None / No difficulty
- 1 = A little / Slight difficulty
- 2 = Medium / Moderate difficulty
- 3 = A lot / Severe difficulty
- 4 = Often cannot do the task
- Scoring Procedures:
- Direct summation scoring: Ratings for each item are summed to generate an overall Functional Impairment Score.
- Full 5-Item Scale Score Range: 0 to 20.
- Optimized 4-Item Scale Score Range: 0 to 16.
- Direction of Scoring: Higher total scores indicate greater functional impairment, role disability, and behavioral manifestation of distress.
- Reverse Scoring: None. All items are positively keyed toward impairment.
11. Permissions & Fee and Test Year
The Function Assessment Scale was developed and published in 2025 as part of the Sierra Leone Perinatal Mental Health research initiative led by Queen Margaret University and the University of Sierra Leone. In alignment with global public health ethics and the drive to enhance maternal mental health resources in low- and middle-income countries, there is no fee required to access or administer the scale for academic research, non-profit clinical practice, or humanitarian programming.
Researchers and clinicians intending to implement, adapt, or translate the Function Assessment Scale are requested to contact the corresponding author to obtain permission and register their field implementation:
- Contact Person: Abdulai Jawo Bah
- Affiliation: Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom
- Correspondence Email: [email protected]
12. 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 impairment measurement: Adapting the Short-Form 36 for use in Uganda. The Lancet, 359(9323), 2087–2088. https://doi.org/10.1016/S0140-6736(02)08595-9
Haroz, E. E., Bass, J., Lee, C., Murray, L. K., Robinson, W. C., & Bolton, P. (2014). Measuring functional impairment in global mental health: Performance of the World Health Organization Disability Assessment Schedule 2.0 and a culture-specific function scale in low-resource settings. Global Mental Health, 1, e19. https://doi.org/10.1017/gmh.2014.19
World Health Organization. (2001). International Classification of Functioning, Disability and Health: ICF. World Health Organization. https://apps.who.int/iris/handle/10665/42407