iam sorry ,that was a spelling mistake ,i meant the reaction time,one of the reason why the indian defence planners were eager for the arrow system was that it had a very short reaction time.
i will give a scenario as an example of the reaction time:
let us assume that usa launches an icbm at india(a distance of 12000 kms) and this missile has a velocity of ,let us assume 12000kms/hr,then the missile would take atleast an hour to hit its target in india,but if the missile launch were picked up by the indian spy satellites,then the indians would have adequate time to predict the intended target of the missile(maybe not accurately) and activate their atbm missile batteries (let us assume it takes them 20 minutes to do so) and also to activate their civil defence forces and the disaster management personnel.
but on the other hand let us assume that the pakistanis launch a short range ballistic missile from lahore to delhi (a distance of around 300 kilometres) and that the missile's speed is let us say 5 mach(5940 kms/hr or 1.65 kms/sec ),then the missile will have a flight time of approximately 180 seconds ,ie around 3 minutes,the advantage of the arrow is that it can be prepared for action in such a short time and would still have a very high degree of interception accuracy.the time limit would however be too short to activate the civil defence and disaster management forces and hence the missile requires to be highly reliable and accurate.
india and israel share a parrallel that both have share their borders with hostile neighbours armed with ballistic and cruise missiles.