TransDow Trading System Test
May 8, 2013 - Technical Trading
A subscriber inquired about the TransDow trading strategy, which seeks to exploit a relationship between the Dow Jones Transportation Average (DJTA) and the Dow Jones Industrial Average (DJIA). Specifically, this strategy:
- Computes the 10-week simple moving average (SMA) of the ratio of the weekly closes of DJTA to DJIA.
- Enters (exits) a long position in a risky asset, such as iShares Dow Jones Transportation Average (IYT), whenever the ratio crosses above (below) the SMA,
- Includes a stop-loss of -4% for any week, requiring a fresh signal for re-entry (the ratio crossing below the SMA and then crossing above it again).
The strategy creator finds that this strategy works well over a very long sample period based on indexes. However: (1) development of the strategy may impound data snooping bias; (2) the sample appears to have a lucky start for the strategy (just before the 1929 crash); and, (3) the testing methodology appears to ignore trading frictions (both from weekly signals and from transforming an index into a tradable asset), dividends and return on cash. Using weekly closes for DJTA and DJIA since November 2003 and for IYT (dividend-adjusted) since inception in January 2004, all through April 2013 (485-492 weeks), we find that: Keep Reading