The article quotes Paul Samuelson:
> The beauty of social insurance is that it is actuarially unsound. Everyone who reaches retirement age is given benefit privileges that far exceed anything he has paid in — exceed his payments by more than ten times (or five times counting employer payments)!
I checked this using my work history. I download my wage history from ssa.gov, downloaded the payroll tax history from somewhere, and download one year T-bill rates over my working lifetime so far.
It turns out that if the payments from me and my employer had been used to buy one year T-bills, and when those matured they had been rolled over into new one year T-bills, the amount that would be there now would be enough to pay my SS benefit if I started collecting now (2 years before full retirement age) for around 17 years, which happens to be around the life expectancy of a male my age. That's assume the T-bills stop rolling when I start collecting and so there is an uninvested lump sum of cash. Keep rolling over to new T-bills and it can cover several years beyond my life expectancy.
That suggests that at least for workers with salary history similar to mine you could actually have a sound system--we are contributing enough that it should be possible to cover our benefits.
I'm pretty sure this is just a coincidence. People who made more than me would also likely find results similar to mine, but people making substantially less would probably find their benefit exceeds what their contribution could cover.
That's because your monthly SS benefit depends on what your "averaged index monthly earning" (AIME). That's the average you earned a month during your 35 highest earning years with each year indexed to current dollars. The method to go from AIME to monthly benefit amount looks like this (with the specific numbers depending on what you you become eligible to start receiving benefits):
90% of the first $1000 of your AIME +
32% of the AIME over than but less than $6000 +
15% of the AIME at or above $6000
E.g., someone whose AIME is $1k would get $900/month. Some with $10k AIME would get $3100/month. The second person would have contributed 10x as much but only have a benefit 3.4x as much.