The Immortality Institute volunteers have put together an interesting article: "Current government projections may significantly underestimate the future life expectancy of Americans, according to new research from the MacArthur Research Network on an Aging Society published in The Milbank Quarterly. The research finds that by 2050 Americans may live 3.1 to 7.9 years longer than official government projections, resulting in sharply higher costs for government programs that serve older citizens. The findings are based on the premise that the risk of death in the coming decades will be reduced by accelerated advances in biomedical technology that delay the onset and progression of major fatal diseases or that slow the aging process." There is great uncertainty in actuarial projections in recent years, which reflects great uncertainty over the course of future biotechnology. It is clearly the case that vast improvements in life span are possible in a few decades with the right levels of funding and support - the big question is whether that funding and support materializes in time. That is the challenge facing advocates for engineered longevity.