Story: L.A. County has its most accurate count yet of its homeless population

Over three days in January, 5,500 volunteers spread out across Los Angeles County to do the impossible: count the homeless. Results of the survey, released last month by the Los Angeles Homeless Services Authority, estimated a homeless population of 44,359, an increase of 12% since the last survey in 2013.

For the first time, responding to a Public Records Act request by The Times, LAHSA has also released the count at the census tract level, making it possible to show the dispersion of the growing homeless population into nearly every neighborhood.

The map shows a dot for every homeless person counted. The dots are distributed randomly within each of the 1,684 census tracts surveyed and so do not represent the actual location where the homeless person was living. Vehicles and encampments occupied by the homeless are shown as single dots. The survey uses a statistical multiplier to estimate the total number of homeless in vehicles and camps.

Based on an in-depth survey of vehicle and camp dwellers conducted in 2013, the statistical model weights each based on the likelihood it is occupied by individuals or a family and the average number of individuals and family members found in each type:

The ratios used in the calculation are as follows:

Type Percent individuals Percent families Average #individuals Average family size Car 85% 15% 1.17 3.13 Van 91% 9% 1.43 3.97 RV 93% 3% 1.69 3.23 Tent 94% 6% 1.55 2.74 Makeshift shelter 95% 5% 1.81 4.46

For purposes of the map, The Times combined cars, vans and RVs into vehicles and tents and makeshift shelters into camps.

Download the data from the Los Angeles Homeless Services Authority