Читать книгу Encyclopedia of Chart Patterns - Thomas N. Bulkowski - Страница 64

Table 4.2 shows general statistics related to the bearish bat pattern.

Number found. Despite using the high–low price range at most of the Fibonacci turns, as I discussed in the Identification Guidelines, few bats appear in the historical price record. I found them in 491 stocks despite searching from June 1991 to August 2019. Not all stocks covered the entire period and some no longer trade.

Breakeven failure rate. I counted the number of patterns which saw price drop no more than 5% after peaking at D (using the high price at D to the ultimate low). The table shows the failure rate. Anything above zero is too high, but that's in an ideal world. The bear market failure rate, at 4.5%, is terrific. The 17.7% failure rate in bull markets is not so terrific.

When you consider that a declining price trend in bull markets is like swimming against the current, you would expect a high failure rate. Swim with the bear market current and the failure rate drops to one‐fourth the bull market rate.

Average decline after D. Point D ends the pattern and price is supposed to head lower. The average decline is 14.3% in bull markets but substantially better in bear markets, over 20%.

Volume trend, performance. I measured the volume trend using linear regression but often you can tell the trend just by looking at the chart. Figure 4.2, for example, shows volume (E) higher on the left half of the pattern than the right half, so the trend is downward. In fact, the average bearish bat will have a downward volume trend at least most of the time.

Does the volume trend give us any hint of better or worse performance? Not that you'd notice. The widest spread between the two numbers is one percentage point in bull markets. That's probably not statistically significant.