Self-Help Plus to Enhance Early Development: A Cluster-Randomized Controlled Trial of Maternal Mental Health, Child Cognitive Abilities, and Socio-Behavioral Skills Among Refugee Mothers and Their Preschool-Aged Children in Rhino Camp, Uganda

Mothers' psychological distress is assessed using the Kessler Psychological Distress Scale (K6), a 6-item self-report questionnaire that captures symptoms of anxiety and depression experienced in the past 30 days. Each item is scored from 0 (none of the time) to 4 (all of the time), yielding a total score ranging from 0 to 24. Higher scores indicate greater psychological distress. The outcome reflects the change in mean K6 scores from baseline to 12 months post-intervention.

Child psychosocial wellbeing is assessed using the Kiddy-KINDL Parent Version, a validated 24-item caregiver-reported instrument designed to capture health-related quality of life in children aged 3-6 years. Each item is scored on a 5-point Likert scale, and scores are transformed to a total score ranging from 0 to 100, with higher scores indicating better wellbeing. The outcome represents the change in mean Kiddy-KINDL scores from baseline to 12 months post-intervention, based on maternal reports collected by trained enumerators in the caregiver's preferred language.

Mothers' depressive symptoms are assessed using the 9-item Patient Health Questionnaire (PHQ-9). Scores range from 0 to 27, with higher scores indicating more severe depressive symptoms. Change from baseline to 12 months is measured through self-report.

Mothers' posttraumatic stress will be assessed using the PTSD Checklist - Civilian Version (PCL-C). Scores range from 6 to 30, with higher scores indicating more severe PTSD symptoms.

Mothers' anxiety symptoms are assessed using the 7-item Generalized Anxiety Disorder scale (GAD-7). Scores range from 0 to 21, with higher scores indicating more severe anxiety.

Mothers' perceived stress is assessed using the 4-item Perceived Stress Scale (PSS-4). Total scores range from 0 to 16, with higher scores reflecting greater perceived stress.

Positive parenting will be measured using the Positive Parenting subscale of the Alabama Parenting Questionnaire (APQ). Higher scores indicate more frequent positive parenting practices.

Harsh disciplinary practices will be ssessed using the UNICEF MICS6 11-item Discipline Module. Higher scores reflect use of more types of disciplinary actions.

Mothers' subjective wellbeing is assessed using the 5-item World Health Organization Well-Being Index (WHO-5). It contains five questions that assess positive mood, vitality, and general interests. The responses are scored on a scale from 0 (at no time) to 5 (all of the time), and the total score is then multiplied by 4 to give a score range from 0 to 100, with higher scores indicating greater wellbeing.

Mothers' functional impairment is assessed using the 15-item WHO Disability Assessment Schedule (WHODAS-II). Scores reflect levels of functional impairment across several domains. Higher scores indicate greater impairment.

Mothers' psychological flexibility will be measured using the 7-item Acceptance and Action Questionnaire-II (AAQ-II). Scores range from 7 to 49, with higher scores reflecting greater psychological inflexibility.

Children's emotional and behavioral problems will be assessed using the 17-item Pediatric Symptom Checklist (PSC-17), completed by caregivers. Total scores range from 0 to 34, with higher scores indicating more psychosocial difficulties.

Children's psychosocial wellbeing will also be assessed using the self-report version of the Kiddy-KINDL. Scores range from 0 to 100, with higher scores indicating better psychosocial wellbeing.

Mothers' patience is measured using an incentivized investment task adapted from Andreoni & Sprenger (2012). Mothers receive five golden tokens and are asked to decide how many to keep for immediate exchange and how many to invest for a delayed payout (one week later), delivered to their homes. Tokens kept yield a small payout immediately; tokens invested yield double the amount after the delay. The number of tokens invested reflects willingness to delay gratification.

Mothers' risk tolerance is measured using an adapted bomb risk elicitation task (BRET). Mothers are shown five identical boxes: four contain reward tokens and one hides a negative outcome ("a crocodile"). After the boxes have been shuffled, they are asked how many boxes they want to open. If the crocodile is revealed, all earnings are lost; otherwise, each safe box adds to their payoff. Opening more boxes reflects higher willingness to take risks.

Mothers' prosociality is measured using four binary allocation tasks adapted from Fehr et al. (2008) and Bauer et al. (2014). In each game, mothers choose between an equal distribution (1:1) and an unequal one (e.g., 1:0, 1:2, 2:0, or 2:3) affecting themselves and an anonymous peer. Each task is completed twice, once with a recipient described as from the same village (ingroup) and once from a distant village (outgroup), with order randomized. Prosociality is operationalized as the summed difference between tokens given to the recipient and tokens kept by the participant across the eight games, yielding an index score from -6 to +4.

Child patience is measured using an age-appropriate, incentivized behavioral task adapted from Andreoni & Sprenger (2012). Children are given one golden token and asked to choose between two options: exchange the token immediately for one piece of candy, or wait until the end of the session to exchange it for two pieces of candy. This binary choice captures willingness to delay gratification.

Children's risk tolerance is assessed using a simplified bomb risk elicitation task adapted from Crosetto & Filippin (2013). Children are shown three boxes: two contain coins and one hides a 'coin-eating crocodile'. After the boxes have been closed and shuffled, they decide how many boxes to open, knowing that opening the crocodile box results in losing all coins. Opening two or three boxes indicates greater willingness to take risks.

Children's prosociality is measured using four binary allocation tasks adapted from Fehr et al. (2008) and Bauer et al. (2014). Children choose between equal and unequal coin distributions (e.g., 1:1 vs 1:0, 2:0, 1:2, or 2:3) across four games, each completed twice: once with a set of four gender- and age-matched anonymous peers from the same village and once with four peers from a different village. Game partners are represented with AI-generated portraits, and choices are presented using physical bowls and golden plastic coins. Prosociality is operationalized as the summed difference between coins given to the partners and coins kept by the child across all eight games, resulting in an index score from -6 to +4. Change in this index is assessed from baseline to 12 months.

Children's cognitive skills will be assessed using a battery of gamified tasks. Spatial cognition will be measured using 2d shapes. Mathematics ability will be assessed using free counting, give-n, number comparison, and addition/subtraction tasks. Theory of mind will be measured using surprise content and surprise outcome tasks. Language skills will be assessed using TIFALDI.

Food insecurity will be assessed using the Food Insecurity Experience Scale (FIES), an 8-item instrument developed by the Food and Agriculture Organization (FAO). The questions ask about experiences of limited food access over the past 30 days and are calibrated against a global reference from the 2014-2016 Gallup World Poll to allow for cross-country comparability. Responses will be analyzed using Item Response Theory (IRT) models to generate comparable estimates of food insecurity severity and prevalence.

Dietary diversity will be assessed using the Household Dietary Diversity Score (HDDS). The HDDS is a measure of food consumption that reflects a household's access to a variety of foods. It's based on households' self-reporting of the 12 food groups consumed in the previous 24 hours.

Child malnutrition will be assessed using the Height-for-Age Z-score (HAZ). The HAZ is a standard statistical measurement that represents how a child's height compares to a reference population of the same age and sex. It's used to assess long-term nutritional status and can indicate chronic malnutrition or stunting. A HAZ score below -2 is considered stunted, indicating that the child is significantly shorter than the average height for their age. A score above +2 would suggest the child is taller than the average height for their age.

Social capital will be assessed through survey items capturing group membership, civic participation, and interpersonal trust.