The policy rate minus core CPI inflation over the past year, read at the end of each month: how hard monetary policy is braking. The threshold is the series' own ten-year mean plus one point, so each region has a baseline that fits its history and nothing is estimated. It triggers only while the policy rate is also higher than six months earlier; above the level with rates on hold or falling it is on Watch.
Threshold source: worldstat.us construction: the real rate a point above its ten-year mean while the policy rate is higher than six months earlier. How thresholds are chosen
A worldstat.us rule with no published track record. The ten-year mean includes the zero-rate years, which lowers the baseline everywhere.