Jason Zweig writes:
Many analysts have warned lately that Prof. Shiller’s long-term stock-pricing indicator [CAPE] is dangerously high by historical standards…..If only things were that simple, Prof. Shiller says. “The market is supposed to estimate the value of earnings,” he explains, “but the value of the earnings depends on people’s perception of what they can sell it again for” to other investors. So the long-term average is “highly psychological,” he says. “You can’t derive what it should be.” Even though the CAPE measure looks back to 1871, using data that predates the S&P 500, it is unstable. Over the 30 years ending in 1910, CAPE averaged 17; over the next three decades, 12.7; over the 30 years after that, 15.7. For the past three decades it has averaged 23.4. Today’s level “might be high relative to history,” Prof. Shiller says, “but how do we know that history hasn’t changed?” So, he says, CAPE “has more probability of predicting actual declines or dramatic increases” when the measure is at an “extreme high or extreme low.” …..Today’s level, Prof. Shiller argues, isn’t extreme enough to justify a strong conclusion. So, he says, he and his wife still have about 50% of their portfolio in stocks.
Read more at Robert Shiller on What to Watch in This Wild Market – MoneyBeat – WSJ.