This report aims to support the Illinois Human Services Commission in its effort to fulfill its charge to "undertake a systematic review of human services programs with the goal of ensuring their consistent delivery in the State of Illinois" and to "make recommendations for achieving a system that will provide for the efficient and effective delivery of high quality human service" by outlining basic population and demographic trends that impact human services and by diving deeper into seven human services categories to identify who is in need of services and how current realities and trends may impact the level and type of need going forward. The seven categories of human services were chosen based on their diversity, vulnerability in the state budget, and their potential to be impacted by emerging and likely trends. **More than simply a compendium of data on need, this report demonstrates how relatively simple data can inform program and policy decisions, which are far too often made in information voids. With Illinois human services plagued by increasingly scarce resources, cutbacks in services, and program closures in the last few years, such data-driven decision making is more critical than ever. To that end, the report concludes with a detailed account of how all need estimates in the report were developed and practical recommendations for how the state can incorporate this type of analysis into regular planning.