The Williams Institute, June 2016: “Population-based surveys, meaning those that are designed to allow researchers to generalize findings to the population, rarely ask questions to identify transgender people and, therefore, cannot be used to provide estimates of the size and characteristics of the transgender population. The federal government administers several large, national population-based surveys like the American Community Survey and the National Health Interview Survey that track the demographics, health and well-being of U.S. residents. Unfortunately, these surveys do not currently measure gender identity. However, there are several state-level population-based surveys that identify transgender respondents and can be used to estimate the size and characteristics of the transgender population. In 2011, Gary J. Gates utilized two state-level population-based surveys that collected data from 2003 in California and from 2007 and 2009 in Massachusetts to estimate that 0.3% of the U.S. adult population, roughly 700,000 adults, identified as transgender. Since then, more state-level data sources have emerged that allow us to utilize an estimation procedure that would not have been possible with the limited data available in 2011. Compared to the data used in Gates’ study, these new data sources provide more recent data (2014), larger sample sizes, and more detailed information about respondents. This allows for the development of more recent, detailed, and statistically robust estimates of the percentage and number of adults in the United States who identify as transgender. This report utilizes data from the CDC’s Behavioral Risk Factor Surveillance System (BRFSS) to estimate the percentage and number of adults who identify as transgender nationally and in all 50 states. We find that 0.6% of U.S. adults identify as transgender. This figure is double the estimate that utilized data from roughly a decade ago and implies that an estimated 1.4 million adults in the U.S. identify as transgender. State-level estimates of adults who identify as transgender range from 0.3% in North Dakota to 0.8% in Hawaii. In addition, due to current state-level policy debates that specifically target and affect transgender students, we provide estimates of the number of adults who identify as transgender by age. The youngest age group, 18 to 24 year olds, is more likely than older age groups to identify as transgender.”