Table 1.

Example of Theory-based Approach for Development of CHoBI7 mHealth Messages: Psychosocial Factors and IBM-WASH Dimensions

Psychosocial Factor	Factor Definition	Behavior Change Technique	IBM-WASH Dimension	Example Messages	Hypothesized Change with Intervention
Self-Efficacy	The belief in one’s capabilities to organize and execute the courses of action required to manage prospective situations. (Bandura et al. 1997)	mHealth messages providing information on actionable tasks	Structural (Gender Roles)/ Individual	Voice Message Dr. Chobi Apa: How are you brother? How is Aklima and your children?	Higher acceptability of WASH behavioral recommendations among men
				Husband: Yes, good! My children got frequent diarrhea and sometimes we needed to hospitalize them before. Now, they remain healthy.	Higher self-efficacy among male household members
				Dr. Chobi Apa: Why do you think they remain healthy now?
				Husband: Because my family and I now boil and safely store our drinking water and wash our hands with soapy water after defecation, after cleaning a child’s feces and anus, before preparing food, and before eating or feeding children. See, you phoned and texted me which I have shared with my family and followed all the instructions.
		mHealth messages encouraging the use of enabling technology	Habitual	Text Message To keep your water safe to drink, always put your boiled water in the blue bucket with the lid on. Never put your hands into this water, always use the tap. Keep your family happy and healthy!	Higher self-efficacy and convenience of WASH behavioral recommendations
Descriptive Norms	Perceptions about which behaviors are typically performed by others (Cialdini et al. 2006)	mHealth messages describing the proportion of others in the community performing the same behavior	Community	Voice Message I am Dr. Chobi Apa from Mohakhali Cholera Hospital. How are you? We have found that 80% of individuals in your neighbourhood reported washing their hands with soap before feeding their child this week. Like others in your neighborhood, always wash your hands with soap before preparing food and feeding your child. Make sure there is always soapy water present within 10 steps of your cooking area. Keep your family healthy and happy!	Higher descriptive norms of WASH behavioral recommendations
		mHealth messages from Aklima, a woman who brought her child to a health facility for diarrhea treatment, and who learned proper handwashing and water treatment behaviors from Dr. Chobi.	Interpersonal	Voice Message This is Dr. Chobi Apa. Aklima is here with me again today and wants to share her story with you. Aklima: My son was very sick; he almost died. We took him to the hospital and the doctors gave him treatment. Before I left the hospital, they gave me a nice red handwashing bucket and blue water bucket. Dr. Chobi Apa told me about washing my hands with soap at four key times: before I prepare food, before I eat, and after I use the toilet or clean my child’s feces or anus. I have followed all these instructions all the time, and my family is now healthy and happy! Dr. Chobi: Thank you Aklima for sharing your story! Did you hear how well Aklima is doing now? Are you also practicing these safe practices and staying healthy?	Higher descriptive norms of WASH behavioral recommendations
Emotion of Nurture	The desire to care for someone, and see them develop or grow.	mHealth messages encouraging nurture of young children as a motivator to practice the key behaviors promoted	Interpersonal	Voice Message Diarrhea especially hurts small children. To protect your child from these germs, make sure your whole family washes their hands at 4 key times: after defecation, after cleaning a child’s feces and anus, before preparing food, and before eating or feeding children. Use soapy water each time!	Higher nurture for young children
Emotion of Disgust	Revulsion that is occasioned by the sight of excreta, rotten food, slime, and bugs. (Curtis et al. 2001)	mHealth messages encouraging the emotion of disgust as a motivator to practice the key behaviors promoted	Individual	Text Message If you don’t wash your hands after using the toilet, you’re eating feces when you’re eating your food. There are lots of germs in feces, and you may have diarrhea again.	Higher disgust
Remembering	To perform a behavior, it has to be remembered at the right time/situation. (Tobias et al. 2009)	mHealth messages reminding households to perform the key behaviors promoted	Habitual	Text Message Have you made a habit of drinking safe water and washing your hands with soap to create a shield for good health? If not, you can start now!	Higher daily remembering of behavioral recommendations