Table 3 Description of trial outcomes, assessment tools, mediators, and covariates. *The starred IDELA, executive functioning skills assessments, anthropometric, and demographic measures were previously adapted for the rural Pakistan context for use in the LEAPS efficacy trial [26]. **The SRQ-20 was previously adapted and validated for use in rural Pakistan [56]. All other measures were adapted or developed for use in this trial. All outcomes will be recorded as absolute values, and cluster-level outcomes will be aggregated by averaging the individual outcomes within each cluster

 School Readiness

International Development & Early Learning Assessment (IDELA) [31]*

IDELA assesses the development and early learning, namely school readiness, of young children aged 3.5–6 years old. The tool includes sub-tests for emergent math, socio-emotional development, emergent literacy, and motor skills. The primary outcome will be the IDELA total score, which will be the parameter estimates computed through a Graded Response Model based on the recommendation of the tool developers. Higher scores reflect better outcomes.

 Emergent Math

International Development & Early Learning Assessment (IDELA) [31]*

IDELA subdomain comprising seven sub-tasks assessing emergent math skills. The domain score is computed through a Graded Response Model recommended by the tool developers. Higher scores reflect better outcomes.

 Socio-emotional Development

International Development & Early Learning Assessment (IDELA) [31]*

IDELA subdomain comprising five sub-tasks assessing socio-emotional development. The domain score is computed through a Graded Response Model recommended by the tool developers. Higher scores reflect better outcomes.

 Emergent Literacy

International Development & Early Learning Assessment (IDELA) [31]*

IDELA subdomain comprising six sub-tasks assessing emergent literacy skills. The domain score is computed through a Graded Response Model recommended by the tool developers. Higher scores reflect better outcomes.

 Motor Skills

International Development & Early Learning Assessment (IDELA) [31]*

IDELA subdomain comprising four sub-tasks assessing fine and gross motor skills. The domain score is computed through a Graded Response Model as recommended by the tool developers. Higher scores reflect better outcomes.

 Child Executive Functioning Skills: Working Memory

Corsi Block-Tapping Test [57]*

Direct assessment of child’s working memory skills. The child’s score reflects the longest sequence for which two block series were repeated correctly, plus 0.5 if one longer series was also correctly processed (range 0–4 points). Higher scores indicate better outcomes.

 Child Executive Functioning Skills: Inhibitory Control

Knock and Tap assessment [58]*

Direct assessment of child's inhibitory control skills. Total score is the sum across 16 items (range 0–16 points). Higher scores reflect better outcomes.

Peg Tap assessment [58]*

Direct assessment of child’s inhibitory control skills (range 0–16 points). Total score is the sum across 16 items. Higher scores reflect better outcomes.

 Child Executive Functioning Skills: Cognitive Flexibility

Dimensional Change Card Sort [59, 60]*

Direct assessment of child’s cognitive flexibility skills. Five sub-scores will be examined: total number correct trials on the separated level, pre- and post-switch (0–6 points each); total number correct trials on the integrated level, pre- and post-switch (0–6 points each); and total correct on the border version (0–12 points). Higher scores reflect better outcomes.

 Child General Executive Functioning Skills

Head Toes Knees Shoulders task [61]*

Direct assessment of child’s general executive functioning skills. The assessment contains two sections. Child participants may receive 0 to 20 points for each section. Scores will be presented separately for each section. Higher scores reflect better outcomes.

 Youth Executive Functioning Skills: Working Memory

Backward Word Span Task [62]*

Direct assessment of youth’s working memory skills. The participant’s score reflects the longest sequence for which two series were repeated correctly, plus 0.5 if one longer series was also correctly processed (range 0–6 points). Higher scores reflect better outcomes.

Corsi Block-Tapping Test [63]*

Direct assessment of youth’s working memory capacity. Participants will be administered two tests: a forward and a backward test. A score will be awarded for each test, reflecting the longest sequence for which two series were repeated correctly, plus 0.5 if one longer series was also correctly processed (range for each 0–7 points). Scores will be presented separately for each test. Higher scores reflect better outcomes.

 Youth Executive Functioning Skills: Inhibitory Control

Number Stroop Effect [64]*

Direct assessment of youth’s inhibitory control skills. Points are summed across 20 items to calculate the overall sum score (range 0–20 points). Higher scores reflect better outcomes.

 Youth Executive Functioning Skills: Cognitive Flexibility

Trail Making Task (TMT) [65, 66]

Direct assessment of youth’s cognitive flexibility skills. cores reflect the time for completion in seconds, with the maximum time limit being 300 s (range 0–300). Lower scores indicate a better outcome.

 Youth Personal and Professional Development

Self-reported Questionnaire

Self-reported questionnaire developed for study context which includes items examining aspects of professional and personal development pertaining to autonomy, self-efficacy, self-esteem, professional growth, and aspirations. Mean item scores will be calculated for each domain. This does not include a standardized scale.

 Youth Self-Reported Depressive Symptoms

Self-Reporting Questionnaire 20-Item (SRQ-20) [67]**

Direct assessment of youth self-reported depressive symptoms over the last 30 days. Items are summed for a total score of depressive symptoms over the last 30 days (range 0–20 points). Higher scores reflect poorer outcomes.

 Classroom Structural and Process Quality

To be adapted from the Measure of Early Learning Environments (MELE) module of the Measuring Early Learning Quality and Outcomes (MELQO) tool [54] and the Instrument for Measuring Quality of Early Childhood Education in Colombia (IMCEIC) [55]

Direct Assessment of children’s pre-primary learning environments in LEAPS preschool and comparison classrooms. The 7 major domains are: environment and physical setting, family and community engagement, personnel, interactions, inclusiveness, pedagogy, and play. Mean scores will be calculated from all items (range 1–4 points). Higher scores reflect better outcomes.

 Child's Household Demographics

Child Household Questionnaire, including Socio-Economic Status Index [68]*; Household Food Insecurity Access Scale (HFIAS) [69]*

Household questionnaire including items examining child’s age, child’s gender, parental education, parental employment, assets-based household socio-economic status, and household food insecurity.

 Child Anthropometric Indices

Anthropometric Questionnaire*

Anthropometric Questionnaire collects child age and child growth indicators. Child’s anthropometric z scores will be calculated using WHO Child Growth Standards.

 Youth’s Household Demographics

Youth Enrollment Questionnaire, including Socio-Economic Status Index [68]*; Household Food Insecurity Access Scale (HFIAS) [69]*

Youth Enrollment Questionnaire including items examining the youth’s demographics, such as age, education, marriage status, assets-based household socio-economic status, and household food insecurity.