The Duckworth–Lewis or D/L method is named after the English statisticians Frank Duckworth and Tony Lewis who devised this method for calculating target scores in cricket.
With the help of a developed mathematical data, the value of these two resources is calculated as a percentage.
However this system obviously cannot factor in the reputation/capability of the chasing team when calculating revised targets for them
The DLS target for the team chasing is calculated for a minimum of five overs in a T20I match and 20 overs in an ODI match with the help of a formula.
The formula is calculated as - Team 2's pass score = Team 1's score x (Team 2's resources / Team 1's resources).
Par score refers to the target that the chasing team should have/should have reached after a certain number of wickets have fallen, at which time the match was interrupted for some reason.
Thus, if a team exceeds this par score after the expiry of a certain number of overs from which it is not possible to resume play, then they are deemed to have won the match.
It is worth mentioning that this DLS target keeps changing after almost every second delivery if the match is interrupted. For example, if a team loses a wicket or two in its bid to maintain a par score, the revised target for the next over will increase as the 'wickets left' (shelters) are further reduced.
To arrive at the result of a match, at least five overs in a T20 competition and 20 overs in an ODI must have been bowled during the chase.