The Combating Autism Act (CAA; Public Law 109-416) and the subsequent Combating Autism Reauthorization Act (CARA; Public Law 112-32) established an Interagency Autism Coordinating Committee (IACC) to advise the Secretary of Health and Human Services on issues related to Autism Spectrum Disorder (ASD). One responsibility of the IACC is the development of a strategic plan for ASD research, to be updated yearly. The IACC Strategic Plan, first issued in 2009, was produced by the IACC, composed of federal officials and public stakeholders, with extensive input from researchers, adults on the autism spectrum, parents, advocates, and the general public that was gathered through a series of meetings and public comment opportunities. This inclusive process ensured that the IACC Strategic Plan reflected diverse perspectives from across the autism community. The IACC Strategic Plan is organized around seven general topic areas that are represented in the plan as consumer-focused Questions (e.g., Question 1, "When should I be concerned?" which covers the topic of screening and diagnosis). Each Question is assigned a chapter that provides a description of the state of the science in that area. Each chapter also contains a section describing the research and community needs for its relevant Question; the aspirational goal, or long term vision, for each area; and a list of specific long- and short-term objectives. The objectives were created by the Committee to address critical gaps and opportunities they perceived in the research landscape in 2009. Each objective also includes a recommended budget that serves as an estimate of how much the Committee projects it might cost to conduct the research-related activities described. Each section contains a list of references. The IACC Strategic Plan was updated in 2010 and 2011, adding several new objectives over these years. In 2012, following the reauthorization of the Committee, the plan was updated with advances and new research opportunities. For the 2013 update of the IACC Strategic Plan, the Committee voted to focus on accountability without adding new objectives or re-writing the previous version. With access to an extensive portfolio analysis conducted by the National Institutes of Health (NIH) Office for Autism Research Coordination (OARC) linked to every objective, as well as the annual IACC Summary of Advances documents from past years, the IACC reviewed what has been invested in ASD research in the United States since 2008. Using data from both public and private funders, the IACC determined the level of progress for each of the 78 objectives in terms of the number of projects funded and dollars committed to each objective since 2008. To assess the return on this investment, the IACC also invited a group of external experts to evaluate how research has supported progress toward the aspirational goals in each of the seven chapters of the IACC Strategic Plan. This update summarizes both investment and scientific progress across all seven Questions of the IACC Strategic Plan. Most areas have received extensive investment ($1.5 billion expended from 2008-2012 by federal and private funders) and significant progress has been made since the original Plan was published in January, 2009. According to the PubMed database of biomedical research literature, over 11,000 journal articles on autism have been published since January, 2009, more than double the number published in the preceding 5 years. The world of ASD research has changed profoundly during this period, with increases in United States ASD prevalence estimates, changes in ASD diagnostic criteria, greater understanding of co-occurring conditions and services needs, and new insights from genetics, environmental studies, and neuroimaging into the biology and etiology of ASD. In addition to this review of the investment and progress, the Committee and external experts identified current research gaps, needs and barriers, as well as new opportunities created by advances in the field, which can provide direction for future investment. "ASD Research Progress on IACC Strategic Plan Objectives: Summary of Years 2008 to 2012" can be found in the appendix. ["2011 Strategic Plan for Autism Spectrum Disorder Research" can be accessed in ERIC at ED524623. For "2010 Strategic Plan for Autism Spectrum Disorder Research," see ED524616.]