VERY LONG TERM, 25 years, monthly
The full-stochastics (default, monthly) has done a fine job over the years demarcating bull and bear.
When it dips below 50, the shit tends to hit the fan, long term. The STO closed the year at 47.21, which is where the SHTF zone begins.
Historically, when the monthly Bolinger centerline (20ma) is breached (like now), it tends to take a few months (or years) to recover. The previous breaks in the monthly 20ma since the big 2009 bottom have seen the SPX down ROUGHLY --22% (2011) and down -16% (2015-16).
By comparison, we are roughly down -20% SPX peak to trough 2018.
YOUR NUMBERS MAY VARY
The bear target on the monthly bolinger is the lower band, which we hit in December.
From there, a baby-bear cub will recover in a couple of months, while a giant-grizzly bear will scrape along the lower band for years.
You can see one thing for certain: in the grizzly periods, price has always remained BELOW that bolinger centerline (gold dashed 20ma, monthly).
Monthly chart as of the close, 12/31, end-of-year