“A key difference between probability-based and safety-first approaches is that the probability-based approach is more comfortable with accepting greater volatility for higher return potential and an improved chance for success, while the safety-first approach looks for alternatives that do not expose core retirement spending goals to market volatility. The question is ultimately about which is the best way to be able to spend more than a bond ladder can support: to rely on the excess returns expected to be provided by the stock market, or to rely on the power of risk pooling to bring additional spending power to those facing a higher cost retirement.”