Also looks like Bulkowski doesn't rate them highly based on his testing, and looks like the market (at the moment) agrees:
"Many people look at a gravestone doji with alarm, especially during an uptrend. They believe that it signals a bearish reversal. It does, but only 51% of the time. I call that random. The trend after the reversal does not amount to much, placing the performance rank at 77 out of 103 candles where a rank of 1 represents a trend that really moves. There are exceptions, of course, and a gravestone doji can signal a lasting trend change. The analysis I conducted (see my Candlestick Encyclopedia book) highlights several tips to identify gravestone doji candles that outperform. See the above link."
GXY Price at posting:
$2.95 Sentiment: Hold Disclosure: Held