Edmund Andrews documents some classic White House goalpost-shifting and tricks with numbers in the NYT:

While Mr. Bush has alluded only vaguely to the idea [of “progressive indexing”], White House officials have promoted it in considerable detail. According to one White House chart, people at every income level appear to end up winners.

Middle-income workers, for example, those with average annual earnings of $36,000 today, would receive about $1,380 a month in today’s dollars – about $172 more than today’s system could afford to pay – if they retired in 2050.

Even high-income workers, whose benefits would be trimmed the most, would end up with $1,626 a month, about $100 more than today’s system could afford. “All earnings groups in 2050 would receive higher benefits than the current program can afford to pay,” the White House declared in a briefing paper.

But as Mr. Bush’s critics quickly pointed out, the happy outlook omitted two major points. The first is that, under Mr. Bush’s cuts, Social Security would still not be able to afford all the benefits being promised. The second is that the comparisons look favorable only for people who retire within a few years of 2050.

Using projections by the Social Security trustees, White House officials based their comparison on the assumption that, if nothing changed, the Social Security trust fund would be out of reserves in 2041. At that point, Social Security would be allowed to pay out only as much as it took in through payroll taxes and would have to cut total benefits by about 27 percent.

The problem is that Mr. Bush’s plan would not keep Social Security from running out of money. An apples-to-apples comparison would have to take into account that the government would eventually need to cut benefits or raise taxes even if the government did adopt progressive price indexing.

White House officials contend that the changes Mr. Bush has outlined would close about 70 percent of the long-term deficit, but most analysts say the changes would eliminate less than 60 percent…

White House officials do not dispute those estimates, but they have redefined the problem. Instead of saying they would solve 70 percent of the 75-year deficit, the measure most analysts use, administration officials say the plan would reduce about 70 percent of the deficit in the 75th year of their plan. The difference is worth about $500 billion over 75 years.

“The real question is how close you are to getting the system back to positive cash flow by the final year,” said Andrew G. Biggs, deputy director of Mr. Bush’s National Economic Council. “How much of the final-year deficit does it eliminate? By that measure the plan closes about 70 percent of the deficit.”

The White House also shined up its estimates by comparing benefits for a single year, 2050. If the trust fund became insolvent as projected, benefits for a middle-income worker in 2050 would be only $1,208 a month. Benefits under Mr. Bush’s plan would be $1,380, or $1,532 if the person had a personal account that earned higher returns.

But the comparison is misleading. Mr. Bush’s cuts would begin in 2012, whereas people would be claiming full benefits through 2040 if there were no changes in Social Security.

For more on the 2050 trick, see this Center on Budget and Policy Priorities analysis, which takes apart the briefing paper referred to above in more detail. (I’ve asked them to make it public; no response yet.) And for more on Bush administration’s long history of distorting tax and budget figures, see Chapters 4 and 7 of All the President’s Spin.