It has found the numbers of homeless people in Adelaide are at least three times higher than those reported.
The researchers estimate between 311 and 455 homeless people were living in the Adelaide central business district, far
greater than the 104 reported in the 2001 Census.
The study's authors say the numbers are consistent with those estimated by people working in the homeless sector.
Dr Katrina D'Onise says it's vital to have accurate numbers to plan services, and when those services try to get additional
funding.
She says the reserach suggests the traditional Census techniques are not adequate to count hidden and mobile populations like the homeless.
The next Census is due this year.