One reason to prefer a 75 year horizon is that it is a bit less sensitive to estimations of the state of the world more than 75 years in the future. What are the estimation errors of the figure?

Didn't we fix Social Security in the 1980s one year before it went bankrupt? Now we have 33 years (according to very conservative assumptions). I'm going to go out on a limb and suggest that if we were to spend some time worrying about Medicare first, it wouldn't be a total disaster. Chances are, Social Security will be in better shape a few years from now if we do exactly nothing (since the projections build in unrealistically poor productivity growth, immigration levels, etc.).

I note these arguments about the solvency of SS (over 75 years, forever, whatever period) and am perplexed over why so many people think this matters now, when it never mattered in the past. It certainly didn't matter... [] From 1939 to 1980, when trust fund was kept negligibly small and Paul Samuelson actually wrote "The beauty of social insurance is that it is actuarially unsound" in his famous Newsweek article that praised Social Security "a Ponzi Scheme that works." What mattered back then was current cash flow. [] Nor to the Greenspan Commission of 1983, which created SS's current structure, if you believe its executive director and SS's long-time chief actuary, Robert Myers, in his oral history at SSA.gov: "Q. ... some people rationalize the [trust fund] financing basis by saying that it's a way of partially having the baby boomers pay for their own retirement in advance. You're telling me now this was not the rationale. Nobody made that argument or adopted that rationale? "Myers: That's correct. The statement you made is widely quoted, it is widely used, but it just isn't true. It didn't happen that way ... The main thing that was talked about was how do we fix up the short-range problem. Are you sure we aren't going to have another crisis in 2 or 4 years?... The whole air of crisis in early '83 was let's fix this system up for the next decade..." What mattered to SS's re-designers then was current cash flow. But in the future, will "solvency" matter? Well, look at the Medicare trust fund, it will be exhausted long before the SS trust fund will be. But is anyone planning to cut Medicare benefits when it does, as a result? Of course not -- so what difference will its "insolvency" make? None. They'll just take the current cash flow revenue previously used to pay down the trust fund bonds and use it to pay Medicare benefits directly. Does anybody think SS will be any different when its trust fund runs out? If not, what difference does its solvency make? C'mon, the 75-year solvency of SS never mattered to any politician and never will -- current cash flow is what has always mattered. And the cash flow picture for SS is much worse than its "75-year actuarial" picture. The cash flow needs of SS will grow by two points of GDP -- not of payroll but of GDP, about equal to an 18% across-the-board income tax increase -- in the 2030s at a time when Medicare's cash flow needs will grow by twice as much. Which means actuarial projections for those programs even over a mere 75 years are meaningless, because the cash flow tsunami coming in 25 years is going to cause them to be redesigned then, in light of the 50+% income tax hike (or equivalent) they will be driving. BTW, cash flow is also what stands to drop the credit rating of the US from AAA to "junk" by 2030, according to Standard & Poors. So I just don't understand why so many analysts go on at such great length and detail about 75-year and infinite-horizon "solvency", when it just doesn't matter at all -- and when they know that in only 30 years cash flow will be the killer.

"Why count the taxes that a worker pays during that period but not the benefits that worker will receive in retirement after that period?" Well since the 75 year window resets every year you would have to ask how many workers retirement years are not fully covered within it? An eighteen year old entering the job market today will be 93 in 75 years, a typical college grad will be 97, surely their interests are fully being covered here and for the most part their childrens' too. When the 2030 Report rolls around the window will cover everyone until 2105. At some point I should be able to privilege the current utility of my payroll dollar over some contingent shortfall 90 years from now. If mortality continues to increase in a way that means changing the window to 80 years well fine, but from where I am sitting Infinite Future just looks like a way to pad the bill by $9.3 trillion. I am fifty-one, 2083 seems pretty far from where I am sitting, I don't see that this is my problem in a way that would make it a higher priority than say funding SCHIPS for the kids down the street.

"Myers: That's correct. The statement you made is widely quoted, it is widely used, but it just isn't true. It didn't happen that way ... The main thing that was talked about was how do we fix up the short-range problem. Are you sure we aren't going to have another crisis in 2 or 4 years?... The whole air of crisis in early '83 was let's fix this system up for the next decade..." What mattered to SS's re-designers then was current cash flow." Prefunding is indeed a myth, as of course is the whole 'looting' narrative, though I have a difficult time explaining that to my friends on the Left. The 1983 Reform was designed to put the Trust Fund back in Short Term Actuarial Balance, or 100% reserve in each of the next ten years. As it turned out growth over the next ten years came right in line with the intermediate projections and Social Security achieved Short Term Actuarial Balance in 1993. I am no fan of Reagan or the first Bush, but together they handed Clinton a Social Security system sitting right where the law suggests it should be at any given time, with a Trust Fund Ratio of 100+. Currently the Trust Fund is projected to stay in Short Term Balance until about 2026, the attempt to shift attention to Long Term Actuarial Balance (75 year) and since 2003 Infinite Future Actuarial Balance can fairly or not be characterized as a diversion from the fundamental health of Social Security over the next decade plus. There really is no need to move on this, frustrating though that must be to people who have worked on their SS plans for years.