GAO reviewed the funding of 2000 Census planning and development efforts and the impact it had on census operations. Total funding for the 2000 Census, referred to as the life cycle cost, covers a 13-year period from fiscal year 1991 through fiscal year 2003 and is expected to total $6.5 billion adjusted to 2000 year dollars. This amount was almost double the reported life cycle cost of the 1990 Census of $3.3 billion adjusted to 2000 year dollars. Considering these escalating costs, the experience of the U.S. Census Bureau in preparing for the 2000 Census offers valuable insights for the planning and development efforts now occurring for the 2010 Census. Thorough and comprehensive planning and development efforts are crucial to the ultimate efficiency and success of any large, long-term project, particularly one with the scope, magnitude, and the deadlines of the U.S. decennial census. For fiscal years 1991 through 1997, $269 million was requested in the President's Budgets for 2000 Census planning and development and the program received funding of $224 million by Congress, or 83 percent of the amount requested. According to U.S. Census Bureau records, the bulk of the $86 million in funding received through the end of fiscal year 1995 was obligated for program development and evaluation methodologies, testing and dress rehearsals, and planning for the acquisition of automated data processing and telecommunications support. The U.S. Census Bureau was responsible for carrying out its mission within the budget provided and bureau management determined the specific areas in which available resources were invested. GAO could not determine what effect, if any, that higher funding levels might have had on bureau operations as this is dependent upon actual implementation and the results of management decisions that may or may not have occurred. According to bureau officials, early planning and development efforts for the 2000 Census were adversely affected by lower funding than requested for fiscal years 1993 through 1997. They identified 10 areas where additional funding could have been beneficial. These included difficulties in retaining knowledgeable staff, scaled back plans for testing and evaluating 1990 Census data, delays in implementing a planning database, and limited resources to update address databases. The bureau's experience in preparing for the 2000 Census underscores the importance of solid, upfront planning and adequate funding levels to carry out those plans.