examined in Model 1, and all interaction terms with child gender were subsequently included in Model 2.

Interactions from the fully interacted model were further examined by calculating simple slopes and plotting marginal means of child development scores for boys and girls at varying levels of the risk/protective factor (i.e., at values of 0 or 1 for dichotomous variables and from -1 to 1 standard deviations below and above the mean for standardized continuous variables).

# **Results**

## **Descriptive statistics and bivariate associations of key variables with child gender**

Table 1 summarizes the descriptive statistics and bivariate associations in order to understand how the distribution of key risk and protective factors and relevant demographics varied by child gender for children aged 0-35 months and 36-72 months. Estimated ECE enrollment in our sample was higher (35%) than estimates from the 2019-2020 Pakistan Social and Living Standards Measurement (PSLM) (19%). The estimate of the percentage of the population residing in rural areas aligns with findings from other national surveys (United Nations Population Division's World Urbanization Prospects, 2018). Distributions of child development outcomes and risk and protective factors showed no significant differences by child gender for either age group. Initially, unadjusted results indicated a higher proportion of male caregiver respondents for boy children (84%) compared to girl children (79%) in the older age group. However, this difference was not statistically significant after adjusting for multiple hypothesis testing. Overall, in the sample, a majority of caregiver respondents were male (78%). Additionally, in both age groups, the average age of girls was slightly younger (~1 month) compared to boys, and households with girls had a marginally lower mean monthly expenditure on mobile phone compared to those with boys, though these differences were not statistically significant.

## **Associations between risk/protective factors and child development, and variation by child gender**

Appendix Table I presents results from multivariate regression analyses where each risk and protective factor is examined separately. Table 2 provides results from multivariate regression analyses that simultaneously evaluate all the risk and protective factors together. Figures 1-3 summarize the results using marginal effects.

## **_Parental distress_**

In the analysis for younger children (0-35 months), Appendix Table I Model 1 demonstrates a negative direct association of parental distress (β = -0.12, p<0.001) with early child development (ECD). Appendix Table I Model 2 indicates this direct association was further qualified by a significant interaction between parental distress and child gender interaction (β = -0.13, p=0.031), where the negative association between parental distress and child development was stronger for girls than boys. The interaction term remained significant after adjusting for multiple hypothesis testing. Table 2 presents results after accounting for other risk and protective factors. Here, Model 1 confirms the negative association between parental distress and early child development (β = - 0.09, p<0.001) and Table 2 Model 2 further indicates a stronger negative association with parental distress for girls relative to boys (β = -0.12, p=0.008).

To further probe this interaction, Figure 1 shows the marginal effects of parental distress on early childhood development outcomes for boys and girls based on the estimates in Table 2 9