Methodology of the Social Explorer Population Projections
4. Applying the Method
Applying the method we produced the projections using a “top-down” approach. Projecting total population for Nation level is the first step because projecting the change of a larger population is more reliable. As a second step, we calculated county projections and summed to the state level and then calibrated by Nation level results. After state and county total population projections are created, we produce projections for sex and age components on state and county levels. These numbers are calibrated by already calculated total population numbers. Race projections are assumed to remain constant throughout the projection period, so sex by race tables are projected linearly using projected sex by age data and race distribution in latest ACS 1-yr.