Beyond Technology Labels and Service-Level Classification: Assessing the Structural Condition of Household Onsite Sanitation Facilities in Tamale, Ghana

Monitoring frameworks for household sanitation rely on toilet technology classification and WHO/UNICEF Joint Monitoring Programme (JMP) service levels. Neither measures the physical structural condition of the facility itself. This study introduces the Structural Condition Index (SCI), an equal-weighted, component-based measure of structural condition, applied to 716 onsite sanitation facilities across eight communities in urban Tamale, Ghana. Six structural components (containment unit, toilet slab, superstructure wall, roof, door, and floor) were rated on a three-point ordinal scale and combined into a 0-100 composite anchored to fixed bounds. A two-part regression, equivalent to a one-inflated beta model and fitted with assessor random intercepts, separated attainment of the structural ceiling (SCI = 100) from mean condition below it. Mean SCI was 86.7 (SD 18.4). JMP service level showed a moderate rank-based association with SCI (eta-squared = 0.19). Kumasi Ventilated Improved Pit (KVIP) latrines recorded the lowest mean SCI (77.5) and the widest range of any technology, while flush-to-biodigester systems were the most structurally uniform (mean 98.5). Middle-income community location was the strongest predictor of reaching the structural ceiling (OR = 5.39, p < 0.001), while tiled floor finish (OR = 1.74) and non-durable wall assemblies (OR = 0.61) predicted mean condition below it. Facility age showed no association. Structural condition is a distinct, unmeasured dimension of sanitation performance that technology labels and JMP classification do not capture adequately. Component-level structural assessment can be added to national monitoring instruments to support targeted rehabilitation and minimum construction standards.