Table 2. Findings organised by the BCD checklist.

Component	Sub component	Findings
Behaviour Setting: physical components	Stage: the physical ‘backdrop’ to performing behaviours	• Houses were usually constructed from higher quality materials than the toilets. • Latrines were located at a substantial distance from the home to avoid smell and flies. • Space was not a major constraint in rural areas, but compounds were often full of holes where latrines had collapsed or filled up.
	Infrastructure: physical structures necessary to perform behaviours	• Latrine quality varied: flooring was often earth tamped over a wooden structure, and walls were made of wood, mud, or cloth. Improvements such as roofs, toilet covers, or cleanable flooring were rare. • There was rarely a place for handwashing around the latrine. • A lockable door and a cleanable surface were the most highly valued components of an improved latrine. A ceramic pan, u-bend, and offset pit were least valued. • Seated pans were considered inappropriate for outdoor latrines. • Water was scarce, hampering the ability to flush and clean toilets. • Around 1/3 of total household water was reserved for latrine use including handwashing (20 litres for a pit latrine and up to 60 litres for a pour-flush latrine per day).
	Props: objects necessary to perform behaviours	• Small containers were used to bring water for anal cleansing. • Menstrual materials were either reused or disposed of in the latrine. • Pit latrines were commonly swept with local brooms, sometimes using water, powdered soap or detergent. Improved latrines were cleaned with water and powdered soap and brushes or rubber scrapers.
Behaviour Setting: behavioural components	Routine: the sequence of behaviours regularly performed in a setting	• Household latrines were most commonly used early in the morning, after waking, or after completing morning chores (collecting water, cleaning house).
Behaviour Setting: psychological components	Roles: the part each person is expected to play with regards to the behaviour setting.	• Men took the decision to build or upgrade the latrine, but women could apply pressure to do so. • Pit latrines were usually constructed by men from the household from local materials, whereas a mason was needed to construct an improved latrine. • Women generally performed the day-to-day roles of water collection, disposing of child faeces and cleaning the latrine. • Children sometimes brought water to the latrines for adults.
	Norms: the informal rules governing actions taken (and not taken) in the behaviour settings	• Open defecation was rare and generally frowned upon. • There were different norms around toilet quality within communities. Poor quality toilets were seen as normal and ‘good enough’ for poor people, although bad smells would invite social judgement. Wealthy people were respected and expected to have better quality latrines. • Latrines could be used by passers-by or neighbours.
	Executive brain: explicitly represented mental knowledge, beliefs and planning	• Money was invested in income- generating activity and home improvement before latrines. • Participants were aware that they could be fined for not having a latrine. • There was poor knowledge of the cost of constructing an improved latrine, which was often perceived to be prohibitively high. • Participants considered the amount/cost of water needed in their choice of latrine design but not the costs of emptying pits. • Participants committed to a design, a budget and a mason for an improved latrine upfront, but could collect materials for construction slowly over time.
	Motivated Brain: the goal or benefit an individual will gain from performing a behaviour (e.g., emotional drivers, intrinsic rewards).	• Key motives for building an improved latrine were to protect children and family (Nurture), durability (Hoard), better experience (Comfort; Disgust, Fear), disease prevention (Disgust) and an improved living environment (Create). • Women were motivated by Nurture more than men (the decision makers) who were more commonly motivated to improve living conditions, learn skills and buy mobile phones or modern furniture (Create, Play and Hoard). • Improved toilets could confer respect (Status). However, these motives were mitigated by social norms and negative social judgement if you were perceived to be showing off (seeking Status) or wrongly prioritising income. • Social motives (Affiliation, Attract, Justice, Love) were less cited than personal ones
Biological (body)	Competencies: the skills required to perform a behaviour	• Most males in households had the knowledge and skills to dig and construct basic pit latrines as they had often contributed to building their own homes. • There was an incomplete understanding of the component parts and costs needed for constructing an improved latrine (this required the skills of a mason). • Receiving information on design and cost, and CLTS triggering were reported reasons for building a latrine. • Training and promotional materials to improve knowledge of improved latrines were rarely available.
Context (outside of the setting)	Physical environment	• Life in rural Tanzania is improving, houses are being upgraded and ownership of goods increasing. A lot of building work was in evidence • Scarcity of water is a barrier to upgrading to an improved latrine, which takes more water to flush and clean
	Biological environment	• The environment around homes is contaminated with human and animal faeces.
	Social environment	• Neighbours came together at times of sickness and death, for agriculture, or to manage community schools, but not for latrine building. • Loans were not considered for latrines because interest rates are high (saving was preferred). • Recall of visits by local health officers was low, but respondents reported regular attendance at village meetings and church, where sanitation and hygiene issues were occasionally discussed. • Discomfort with talking about defecation and latrines was evident.