one stock takes about 40 minutes. Running one system through all 65 stocks takes
about 45 hours. And I had to do 10 tests like this. I dare to say that no one has ever
done such a thorough back testing of their systems before they try to sell them to
you for prices many times higher than the price of this book.
Also, even if I wanted to test each stock 20,000 times or more, I wouldn’t be
able to do so in a convenient manner with this many stocks. Excel can only hold a
little more than 65,000 rows of data, and with 65 stocks tested at 1,000 times each
per exit concept, that’s exactly how many rows of data each Excel file will hold.
We have simply reached the ceiling for what today’s computers and software pack-
ages allow us to do.
Before we move on, I also would like to point out that you could use this type
of testing procedure to test your entry rules as well. This works especially well if
you use indicators and patterns that can vary in length and lookback periods, such
as moving averages and crosses above and below the highs and the lows over a cer-
tain number of days.CHAPTER 19 Placing Stops 217