Some observations on the current PE10:
1) Some analysts have noted that the present CAPE (PE10, which is 35.09) is high partly because of the low corporate earnings in the aftermath of the 2008 financial crisis, and that as these bad years fall off the back of the 10 year data set, the average earnings would go up and the CAPE would go down, which would indicate maybe stocks aren't quite so overvalued . I looked at what the "PE8" would be--stock price /inflation adjusted earnings for only the last
8 years, and that number is 31.23. So, if over the
next 2 years, stock prices and earnings stay relatively stable, it is true that the CAPE will decrease into "slightly less overvalued" territory.
but:
2) The "PE1" (includes only last year's earnings) is over 55.
Maybe that's some sort of statistical/calculation artifact. Here are the other "PEs, rounded to the nearest whole number:"
PE10: 35
PE9: 32
PE8: 31
PE7: 31
PE6: 31
PE5: 32
PE4: 33
PE3: 35
PE2: 38
PE1: 55
For geeks: The CAPE calculator I found at
this site makes it easy to do this sort of lookback. Unfortunately, the site/calculator does >not< include a function to find the mean/median CAPE over various time periods, it only figures it for the whole data set (1873(?) to present). The site does offer CSV data of the Schiller series for those who want to torture the data even more in their own spreadsheet.