Here's the whole paper:
https://crr.bc.edu/working-papers/how-best-to-annuitize-defined-contribution-assets/About a third is in (relatively) plain English. It discusses why people might want to use annuities and why they might not (both rational and irrational reasons). This includes the newer advanced life deferred annuities ("longevity insurance"). A good summary of the pros and cons.
The paper compares four options: the baseline (drawing SS at age 6
5); (1) buying an immediate annuity at age 6
5 (with 20% or 40% of retirement assets); (2) spending an amount equal to SS's
PIA (full retirement benefit) out of 20% or 40% of retirement assets until age 70 or assets depleted, then taking SS; and (3) buying longevity insurance with 20% of retirement assets.
Generally, non-annuitized assets are drawn down according to RMDs. But if one buys longevity insurance, this doesn't make sense, because at age 8
5 another income stream kicks in. So the researchers looked at two cases: (a) drawing down according to RMD (i.e. underspending), and (b) spending everything between ages 6
5 and 8
5.
A discussion of the results starts on p. 26 (pdf p. 27). Table 3 summarizes the results. The lower the number, the less you have to spend to get the same result as the baseline. The two cases that came out best were: using 40% of assets to fund income until age 70 and then drawing SS; and buying longevity insurance (spending down everything by age 8
5).
A concern with the latter is that you don't have reserves for an emergency around age 8
5. The next three tables in the results section show how good the strategies are if one assumes random "shocks" (needs for sums of cass). The wealthier you are, the more you can survive shocks even after spending money on annuities (because you're getting higher income from the annuities).
Perhaps it would only have made a marginal difference, but they might have also considered buying a
temporary life annuity to serve as the bridge to SS. That's an annuity that would pay out an income stream from, say, age 6
5 to age 70 or until death, whichever came first. Since you're betting that you'll live to collect SS at age 70, a temporary life annuity just increases the bet a little. And because you forfeit some money if you don't make it to 70, that temporary annuity costs less than "self-funding" the bridge.
