Very interesting how its all within 40-60% of what happens next. I don't consider the 6-8 down days in a row to be at all significant because its based on such a small sample size. It would be interesting if they broke it down even further, like less than and greater than 1%. For example, 3 days of great than 1% down might give a better signal than 3 days of less than 1% down each.
The 3-day pattern shows a real edge and has a long history. I remember reading about using the 3-day rule in a book on swing trading many years back by Marc Rivalland. I think he credited some of WD Gann's trading tactics as a source. For example, Marc looked for 3 consecutive (or almost consecutive) days in an uptrend which showed lower highs and lower lows (disregard opens and closes). After the third day he recommended setting a buy order just above the day's high with a stop-loss below the same day's low. Not much more to it than that.