Every ten years, the census attempts something that sounds simple and is not: counting every person living in the country exactly once, in the right place. People who move during the counting period, families doubled up in one household after a job loss, and residents wary of sharing information with the government all make an exact count difficult to achieve. Because the results determine the number of representatives each state receives and the distribution of billions of dollars in federal funding, even a small undercount in a fast-growing area can mean that area is underrepresented and underfunded for the following decade.