Net run rate (NRR) is a statistical method used in analysing teamwork and/or performance in cricket.
[1] It is the most commonly used method of ranking teams with equal points in limited overs league competitions, similar to goal difference in football.
The NRR in a single game is the average runs per over that team scores, minus the average runs per over that is scored against them.
[2][3] This is the same as the weighted average of the run rates scored in each match (weighted by the lengths of the innings batted compared to the other innings batted), minus the weighted average of the run rates conceded in each match (weighted by the lengths of the innings bowled compared to the other innings bowled).
This is not usually the same as the total or average of the NRRs from the individual matches in the tournament.
Also, while it measures how quickly teams score and concede runs, this is not at all the same as how big the teams' margins of victory or defeat are (as it ignores wickets lost), and so ranking sides by NRR does not rank them by size of victory.
For two teams which have just played, the winning side will have a positive Match NRR, and the losing side will have the negative of this (i.e. the Match NRRs will be additive inverses, summing to zero).
Usually, runs and overs are summed together throughout a season to compare teams in a league table.
The exceptions to this are: All scenarios assume One Day International rules with 50 overs per side.
Just as explained in the scenarios above, the NRR is not the average of the NRRs of all the matches played, it is calculated considering the overall rate at which runs are scored for and against, within the whole group.
Here is an example South Africa's net run rate in the 1999 World Cup.
Teams opposing South Africa scored: Again, with Sri Lanka, England and Kenya counting as the full 50 overs as they were all out, the run rate scored against South Africa across the five games is calculated on the basis of 851 runs in a total of 250 overs, an average run rate of 851/250 = 3.404.
In the language of Duckworth-Lewis-Stern, teams have two resources with which to score runs − overs and wickets.
[8] For example, in the 2013 Champions Trophy Group A: This fact can encourage a team to play in an overly aggressive manner, to maximise NRR by batting with next to no regard for preserving wickets, when the required run rate alone seems low, which can then put the team in danger of losing.
[9] A team may choose to artificially reduce their margin of victory, as measured by NRR, to gain an additional advantage by not disadvantaging their opponent too much.
For example, in the final round of matches in the 1999 World Cup Group B, Australia needed to beat West Indies to progress to the Super Six stage, but wanted to carry West Indies through with them to the Super Six, rather than New Zealand.
It was therefore to Australia's advantage to reduce their scoring rate and reduce their margin of victory, as measured by NRR, to minimise the negative impact of the match on West Indies' NRR, and therefore maximise West Indies' chance of going through with them.
This is similar to the way a narrow victory for one side in a game of football may enable both sides to progress to the next stage, e.g. West Germany v Austria in the 1982 World Cup.
A number of alternatives or modifications done to NRR is suggested below as following - Duckworth Lewis Stern method in used Tournament NRR as present, but when a side batting second successfully completes the run chase, use the Duckworth-Lewis method to predict how many runs they would have scored with a full innings.
This means the calculation would be done on the basis of all innings being complete, and so would remove the criticisms of NRR penalising teams which bat second, and NRR not taking into account wickets lost.
This would make every innings in the tournament the same length, so would remove all the criticisms above.
Calculate tournament NRR as the total or average of the individual match NRRs.
An example of when using this would have made a difference was the 1999 Cricket World Cup Group B.
New Zealand and West Indies finished level on points.
Therefore, New Zealand progressed to the Super Six stage and West Indies were eliminated.
Split teams level on points using the results from the matches between them.
[12][13] An example of where a team progressed further because of a head-to-head result taken into account, was in the 1999 World Cup semi-finals when South Africa vs Australia played to a tie but Australia progressed due to them beating South Africa in the group stages, even though South Africa won more matches.
Alternatively, stage a play-off match between the teams level on points.
However, organising this at very short notice may be difficult, or the teams may be in the middle of a league table with no promotion or relegation or progression at stake, so there may be no appetite for a play-off match.
These two methods both also run into difficulties when three or more teams are level on points.