Population and Population Forecasts
Suggested regional control totals, developed using the 0.5 migration secnario, will be provided to the MPO. These control totals are a starting point for the MPO to begin working on TAZ level demographic assignment and can be used as is or can be adjusted by the MPO. TPP recommends that the 0.5 migration scenario be used to develop all forecast year control totals unless the local area is familiar with a condition that might cause the control total to deviate from the state produced totals. With regard to regional population control totals, it is recommended that the Texas State Data Center (TSDC) be referenced when developing the region's base and forecast year(s) population control totals. The TSDC maintains and estimates population control totals for all counties in the State of Texas. Historical control totals can also be obtained as well. When developing the forecast year(s) control totals, the TSDC provides three different growth scenarios based largely on migration and emigration rates of 0.0 (zero migration, population represents births and deaths only), 0.5 (one half of the migration rate between 1990 and 2000) and 1.0 (equal to the migration rate between 1990 and 2000).
Once the regional control totals are developed the MPO will then need to allocate the population to individual zones. The base year allocation process can draw on the most recent census data as a tool and benchmark for appropriate allocation. For forecast years the MPO can employ a number of techniques to support the allocation process such as the use of a land use model, a Delphi panel, an incremental allocation process employing districts and zones or professional judgment.
Following is a link to the Demographic Guidebook: http://ttiresearch.tamu.edu/g-lobaugh/guidebook/.