Abt Associates has been in the forefront of efforts to measure the condition of the public housing stock and the costs of bringing this resource up to a standard state. In 1985, Abt developed the groundbreaking “observable systems” methodology and applied it in the first capital needs assessment for the U.S. Department of Housing and Urban Development. Thirteen years later, Abt updated and refined these estimates. Both studies were influential in setting appropriation levels for public housing rehabilitation and revitalization. By 2008, many aging public housing units across the nation had undergone varying degrees of renovation. At that time, it became clear to Congress that to complete the job, additional government funding would be needed. To determine the dollar amount, Abt Associates conducted a new study, "Capital Needs in the Public Housing Program," which compared existing modernization needs and accruing needs to those from the previous 1998 assessment. The analysis included a statistically representative sample of 550 properties at 140 public housing developments. In addition to computing the cost to modernize the country’s public housing stock, the study shed light on how public housing agencies estimate capital needs and whether improving the inspection system would generate useful estimates of modernization needs in the future. The results were presented to Congress in the summer of 2011.