The true poverty rate for Americans 65 years and older could be nearly twice as high as it is recorded now, according to a revision of an old, poverty-determining formula.

The original National Academy of Science's government formula, created in 1955, doesn't take account of rising costs of medical care and other factors.

The updated formula would put the poverty rate for older Americans at 18.6 percent, or 6.8 million people, compared with 9.7 percent, or 3.6 million people, under the existing measure.

If the academy's formula is adopted, a more refined picture of American poverty could emerge.

The result could lead to shifts in how billions of federal dollars for the poor are distributed for health, housing, nutrition and child-care benefits.

The overall official poverty rate would increase, from 12.5 percent to 15.3 percent, for a total of 45.7 million people, according to rough calculations by the Census Bureau.

Next week, the Census Bureau will publish official poverty figures for 2008 with a cautionary note about the shortcomings.