Access to high-quality childcare significantly improves children's long-term outcomes. However, access to and use of childcare services are unevenly distributed, leading to growing inequalities in later life. Families with low incomes are 50% less likely to use formal childcare than high-income families, and when they do, it is often for older children and less frequently. Research has shown that cost, location, and quality influence childcare usage, but policies designed to address these barriers haven't effectively reduced the gap. This project takes a fresh approach, combining insights from sociology, economics, demographics, and social policy within a framework known as "complex contagions." The goal is to understand how formal childcare spreads—or doesn't—among low-income families and to identify the barriers that prevent its wider adoption. In a "complex contagion," people only adopt a new behavior, like using formal childcare, when they are repeatedly exposed to it from multiple, diverse people in their social networks. Low-income households tend to have personal networks with long, weak ties and closely-knit groups, making it harder for new childcare strategies to take hold. This project explores how childcare strategies within work, family, and neighborhood networks influence the choices of low-income families. The research uses unique, linked administrative and survey data to examine how childcare strategies spread across these networks. By analyzing this network data with advanced techniques like multichannel sequence analysis, the project aims to uncover how networks shape childcare decisions over time. Ultimately, this study will not only change how we understand childcare strategies but also offer new insights into broader social policies and how behaviors spread within communities.