At a simplistic level, this approach could tell us that if the forecast is above the target, then the stance should be tightened and vice versa. It does not tell us how the forecast will change if interest rates are changed, although different scenarios on different interest rate assumptions can be run.
However, this is out of reach at the European level for the time being. Another way is to eliminate unreliable methods for quality adjustments so that the applied methods by individual “price collectors” will on balance result in unbiased estimates of the true price change.