With limited funds available for social investment, policymakers and philanthropists are naturally interested in supporting programs with the greatest chance of effectiveness and the ability to benefit the largest number of people. When a program rises to the fore with strong, proven results, it makes sense to ask whether that success can be reproduced in new settings. Program replication is premised on the understanding that many social problems are common across diverse communities -- and that it is far more cost-effective to systematically replicate an effective solution to these problems than to continually reinvent the wheel. When done well, replication of strong social programs has the potential to make a positive difference not just for individual participants, but indeed for entire communities, cities and the nation as a whole. Yet despite general agreement among policymakers and philanthropists about the value of replication, successful efforts to bring social programs to scale have been limited, and rarely is replication advanced through systematic public policy initiatives. More often, replication is the result of a particular social entrepreneur's tireless ambition, ability to raise funds and marketing savvy. The failure to spread social program successes more widely and methodically results from a lack of knowledge about the science and practice of replication and from the limited development of systems -- at local, state or federal levels -- to support replication. Fortunately, there seems to be growing awareness of the need to invest in such systems. For example, the 2009 Serve America Act included authorization for a new Social Innovation Fund that would "strengthen the infrastructure to identify, invest in, replicate and expand" proven initiatives. The Obama administration recently requested that Congress appropriate $50 million to this fund, with a focus on "find(ing) the most effective programs out there and then provid(ing) the capital needed to replicate their success in communities around the country." But more than financial capital is required to ensure that when a program is replicated, it will continue to achieve strong results. Over the past 15 years, Public/ Private Ventures (P/PV) has taken a deliberate approach to advancing the science and practice of program replication. Through our work with a wide range of funders and initiatives, including the well-regarded Nurse-Family Partnership, which has now spread to more than 350 communities nationwide, we have accumulated compelling evidence about specific strategies that can help ensure a successful replication. We have come to understand that programs approach replication at different stages in their development -- from fledgling individual efforts that have quickly blossomed and attracted a good deal of interest and support to more mature programs that have slowly expanded their reach and refined their approach over many years. There are rarer cases in which programs have rigorous research in hand proving their effectiveness, multiple sites in successful operation and willing funders prepared to support large-scale replication. Regardless of where a promising program may be in its development, our experience points to a number of important lessons and insights about the replication process, which can inform hard decisions about whether, when and how to expand a program's reach and total impact. In the interest of expanding programs that work, funders sometimes neglect the structures and processes that must be in place to support successful replication. These structures should be seen as the "connective tissue" between a program that seeks to expand and the provision of funding for that program's broad replication. This report represents a synthesis of P/PV's 30 years of designing, testing and replicating a variety of social programs and explains the key structures that should be in place before wide-scale replication is considered. It is designed to serve as a guide for policymakers, practitioners and philanthropists interested in a systematic approach to successful replication.