# Cyclically adjusted price-to-earnings ratio

Another benefit to investors is getting inflation-adjusted values. A total return CAPE corrects for this bias through reinvesting dividends into the price index and appropriately scaling the earnings per share. Sat, 05 Jan The investment return is thus equal to:

## Shiller PE Ratio Data

Some of our earlier results are also noteworthy: This data set consists of monthly stock price, dividends, and earnings data and the consumer price index to allow conversion to real values , all starting January The price, dividend, and earnings series are from the same sources as described in Chapter 26 of my earlier book Market Volatility [Cambridge, MA: MIT Press, ] , although now I use monthly data, rather than annual data.

Dividend and earnings data before are from Cowles and associates Common Stock Indexes , 2nd ed. Principia Press, ] , interpolated from annual data. Stock price data are monthly averages of daily closing prices through January , the last month available as this book goes to press. Bureau of Labor Statistics begins in ; for years before 1 spliced to the CPI Warren and Pearson's price index, by multiplying it by the ratio of the indexes in January Warren and Frank A.

Pearson, Gold and Prices New York: John Wiley and Sons, This is particularly true for new businesses, but also in well-established firms, earnings can suffer from one-time events. The ratio biggest advantage is taking into account the average earnings of the last years, as opposed to regular pe ratio, which uses only the past months earnings.

The ratio neutralizes the financial outcome of a single year. In times of economic crisis, the earnings of most companies crush. The most famous case was the subprime bubble collapse: The regular pe ratio went from to ! The economy moves in cycles, from expansion to contraction. Most of the time we will be in an economic cyclical growth path, and not in the downtrend.

So when average earnings are down sharply, we can assume the situation will shift. Shiller pe ratio overcomes that issue. Another benefit to investors is getting inflation-adjusted values. The Shiller ratio calculation multiplies the price and earnings by the change in the consumer price index CPI. Investors tend to ignore inflation when comparing numbers, but over a long period of time inflation makes a big difference.

To complete your understanding, read our pe ratio complete guide article. There, you will find great insights about the ratio and other stock market valuations. In most cases, major changes in the Shiller multiplier takes many years.

Because the Shiller PE ratio calculation uses the average earnings of the past 10 years, which are not so volatile. After world war I the U. The Shiller PE ratio started its big move in January , when it was at its lowest — 4. In the following years, stocks prices surged much more than earnings of the companies. It all ended in the stock market crash of October , the Shiller PE ratio then came to a peak of In less than 3 years, the ratio plummeted back to the ground and stopped at 5.