Wade Pfau has a fascinating paper out called “Safe Savings Rates: A New Approach to Retirement Planning Over the Lifecycle”. It’s really just the bones of such an approach; the details need to be fleshed out a lot. But I love the idea that we should get away from thinking about “the number” we need to be able to live comfortably in retirement. The effect of the number is to break life into two — pre-retirement and post-retirement. Your goal pre-retirement is to reach the number, while your goal post-retirement is to spend it down slowly enough that it doesn’t run out before you die.
Pfau’s insight is that, thanks to mean reversion, the number you need at the end of a bear market is actually lower than the number you need at the end of a bull market: If the market’s about to head up, your retirement savings can grow even post-retirement, while if the market is about to fall, you’re liable to lose much more than just your annual expenditures. Instead, says Pfau, stop thinking about stock and just think about flows. Save a set percentage of your salary every year, stick to it, and, it turns out, you’ll be fine:
Starting to save early and consistently for retirement at a reasonable savings rate will provide the best chance to meet retirement expenditure goals. You don’t have to worry so much about actual wealth accumulation and actual withdrawal rates, as they vary so much over time anyway. But the savings plan should be adhered to regardless of whether it seems one is accumulating either more or less wealth than is needed based on traditional criteria.
What’s the percentage? That’s the crucial question. Pfau makes a very basic calculation that for someone on a constant real wage, saving for 30 years and then living for another 30 years on 50% of their final salary, saving about 16% of your salary each year into a portfolio of 60% stocks and 40% bonds will put you into safe territory.
Of course, real wages aren’t constant over time, and all the other figures are highly variable too. But the bigger message certainly resonates with me: Expend less effort on trying to boost your annual returns, when you have very little reason to believe in your alpha-generation abilities, and spend more effort on maximizing your savings every year.
Investing can be exciting, especially when it’s done wrong. You follow the markets rising and falling, you obsess about your retirement-fund balance, you rotate out of this and into that, you read books and magazines and blogs to try to learn more about what to do. You might even, in a moment of weakness, find yourself watching CNBC. Budgeting, by contrast, is like going on a diet: It’s a drag, and it’s hard to get any pleasure or excitement out of it. But the latter is much more likely to get you well-set in retirement than the former.
Update: Matt Yglesias has a this-thing-looks-like-that-thing moment.