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{{Short description|Tie-breaking formula in limited overs Cricket}}
{{EngvarB|date=
{{Use dmy dates|date=July 2016}}
'''Net
The NRR in a single game is the [[arithmetic mean|average]] runs per [[Over (cricket)|over]] that team scores, minus the average runs per over that is scored against them. The NRR in a tournament is the average runs per over that a team scores across the whole tournament, minus the average runs per over that is scored against them across the whole tournament.<ref name="ICCPH">
A positive NRR means a team is scoring faster than its opposition overall, while a negative NRR means a team is scoring slower than the teams it has come up against.<ref>
NRR has been criticised as hard to understand
In the [[Cricket World Cup]], the first use of NRR was in the [[1992 Cricket World Cup|1992 tournament]].<ref>{{cite news |url=https://news.google.com/newspapers?id=bpBlAAAAIBAJ&sjid=lJ4NAAAAIBAJ&pg=420%2C3190547 |title=Leander fires out Malik |first=H. |last=Natarajan |publisher=The Indian Express |page=15 |date=19 March 1992 |access-date=15 November 2020 }}</ref> Earlier tournaments used [[run rate]] instead as the tie-breaker.<ref>{{cite news |url=https://news.google.com/newspapers?id=FX5VAAAAIBAJ&sjid=-5YDAAAAIBAJ&pg=3010%2C387454 |title=Border's men face a daunting semi task |first=Martin |last=Blake |date=2 November 1987 |publisher=The Age |access-date=15 November 2020 }}</ref>
==Step by step explanation==
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<math>\text{run rate }=\frac{\text{total runs scored}}{\text{total overs faced}}</math>.
So if a team scores
The concept of net run rate involves [[subtraction|subtracting]] the opponents' run rate from the team's run rate, i.e.
<math>\text{match net run rate }=\frac{\text{total runs scored}}{\text{total overs faced}}-\frac{\text{total runs conceded }}{\text{total overs bowled}} </math>.
For two teams which have just played, the winning side will have a positive Match NRR, and the losing side will have the [[negative number|negative]] of this (i.e. the Match NRRs will be [[additive inverse
Usually, runs and overs are summed together throughout a season to compare teams in a league table. A team's overall NRR for a tournament is not defined as the sum or average of the NRR's from the individual matches, but as:
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*If a match is '''abandoned but a result decided''' by retrospectively applying Duckworth-Lewis, the number of overs assigned to each team for this calculation is the number of overs actually faced by Team 2. Team 1 is credited with Team 2's Par Score (the number of runs they would need to have reached from this number of overs and wickets lost if they were going to match Team 1's score), and the actual runs scored are used by Team 2 for Team 2's innings.<ref name="ICCPH"/>
==
All scenarios assume [[One Day International]] rules with 50 overs per side.
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===3. Side that bats first is bowled out, side batting second wins===
* Team A bat first and are bowled out for
* Team B reach the target off
* Team A's NRR for this game is
* Team B's NRR for this game is
* If 25.667 had been used for Team A's overs total rather than 50, Team A would have finished the match with a positive match NRR, and improved tournament NRR, despite losing. (Similarly Team B with a worsened NRR, despite winning.)
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===5. Both sides are bowled out, side batting first therefore wins===
* Team A bat first, and manage
* In this case, both teams get 50 overs both faced and bowled in the overs column for the season, just as in example 1.
===6. The game ends in a tie===
* Runs and overs are added as in the examples above, with teams bowled out being credited with their full quota of overs. Thus, the match NRR will always be zero for both teams.
===7. Interrupted game with revised D/L target===
* In matches where [[Duckworth-Lewis]] revised targets are set due to interruptions which reduce the number of overs bowled, those revised targets and revised overs are used to calculate the NRR for both teams.
* For example, Team A are dismissed for 165 in 33.5 overs. Team B progresses to 120–0, but play is halted after 18 overs due to rain.
* Six overs are lost, and the target is reset to 150 from 44 overs, which Team B reach comfortably after 26.2 overs.
* Because the target was revised to 150 runs from 44 overs, Team A's total is reset to 149 from 44 overs, thus their RR <math>=
\frac{149}{44} \approx 3.39</math>. Team B's RR, however, is computed as normal: <math>\frac{150}{26.33} \approx 5.70</math>.
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===9. Abandoned game with retrospective D/L result===
*Team A score 254 runs from their 50 overs. Team B have scored 172–4 from 30 overs when the match is abandoned.
*According to [[Duckworth-Lewis]], 6 wickets and 20 overs in hand equates to 44.6% of resources, so Team B has used 55.4% of its resources, so their Par Score is 254 x 55.4% = 140.716 runs. As they are ahead of this, they are declared the winner.
*Team A's RR <math>=\frac{\text{Par Score for Team B}}{\text{Overs faced by Team B}} = \frac{140}{30} \approx 4.67</math>.
*Team B's RR <math>=\frac{\text{Runs scored by Team B}}{\text{Overs faced by Team B}} = \frac{172}{30} \approx 5.73</math>.
==Net Run Rate within a tournament==
===Basic example===
Most of the time, in limited overs cricket tournaments, there are round-robin groups among several teams, where each team plays all of the others. 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.
'''FOR'''
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===Change in NRR through a tournament===
'''After match one'''
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==Criticisms==
===NRR does not accurately reflect margins of victory, as it takes no account of wickets lost===
In the language of [[
*New Zealand
*Sri Lanka comfortably beat England by restricting them to 293–7 from 50 overs, then reaching 297–3 from 47.1 overs, giving them match NRR = (297/47.167) − (293/50) = '''0.44'''.
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.<ref>
▲In the language of [[Duckworth-Lewis method|Duckworth-Lewis]], teams have two resources with which to score runs − overs and wickets. However, NRR takes into account only one of these − overs faced; it takes no account of wickets lost. Therefore, a team regarded as having a narrow victory can have a higher NRR than a team regarded as having a comfortable victory. For example, a team which just manages to win a close game with many overs to spare but with only one wicket in hand is likely to have a higher NRR than a team which paces itself to win comfortably with only a few overs in hand but many wickets.<ref>[http://www.espncricinfo.com/icc-champions-trophy-2013/content/story/640383.html Why net run rate doesn't work] espncricinfo</ref>
▲*New Zealand just beat Sri Lanka by bowling them out for 138, then reaching 139–9 from 36.3 overs, giving them match NRR = (139/36.5) − (138/50) = '''1.05'''.
▲*Sri Lanka comfortably beat England by restricting them to 293–7 from 50 overs, then reaching 297–3 from 47.1 overs, giving them match NRR = (297/47.167) − (293/50) = '''0.44'''.
▲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.<ref>[http://www.espncricinfo.com/icc-cricket-world-cup-2015/content/story/833193.html NZ stutter to win after dominant bowling] espncricinfo</ref>
===NRR may be manipulated===
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 Cricket World Cup#Group
▲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 Cricket World Cup#Group B Table|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. This is because Australia would then have the additional points in the Super Six stage from beating West Indies in the group stage, whereas they had lost to New Zealand in the group stage. 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.<ref>[https://www.theguardian.com/sport/1999/may/31/cricketworldcup1999.cricketworldcup5 Australia pull fast one with go-slow]</ref>
However, this is also likely to be a possibility with alternatives to NRR.
This is similar to the way a narrow victory for one side in a game of [[association football|football]] may enable both sides to progress to the next stage, e.g. [[West Germany 1–0 Austria (1982 FIFA World Cup)|West Germany v Austria in the 1982 World Cup]].
==Alternatives to NRR==
===Duckworth–Lewis–Stern===
Therefore, alternatively, use
▲A number of alternatives or modifications to NRR have been suggested.
▲Use Tournament NRR as present, but when a side batting second successfully completes the run chase, use the [[Duckworth-Lewis method|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. However, this does nothing to alter the fact that when matches are rain-affected, different matches and even two complete innings in one match, can be different lengths long (in terms of overs), and so does nothing about some of the other criticisms above.
▲Therefore, alternatively, use Duckworth−Lewis to predict the 50-over total for ''every'' innings less than this,<ref>[http://www.sporttaco.com/rec.sport.cricket/Net_Run_Rate_alternative_3979.html Net Run Rate alternative] SportTaco.com</ref> even, for example, if a match is reduced to 40 overs each, and a side completes their 40 overs. This would make every innings in the tournament the same length, so would remove all the criticisms above. However, a side will bat differently (less conservatively) in a 40-over innings compared to a 50-over innings, and so it is quite unfair to use their 40-over total to predict how many runs they could have scored in 50 overs.
===Average of the match NRRs===
Calculate tournament NRR as the total or average of the individual match NRRs. This would mean all matches have equal weighting, no matter how long they were, (rather than all batted overs across the tournament having equal weighting, and all bowled overs across the tournament having equal weighting). This would remove the criticisms under the 'Tournament NRR calculation' subheading above. For example, the different teams' tournament NRRs would always sum to zero if the total of the individual match NRRs were used, or if the average of the individual match NRRs were used and all teams had played the same number of games.
An example of when using this would have made a difference was the [[1999 Cricket World Cup#Group
===Head-to-head record or stage a play-off match===
Split teams level on points using the results from the matches between them. However, this unfairly increases the importance of that one match and reduces the importance of other matches in the league, when all matches in a league should be of equal value − the team with the better head-to-head record will have a worse record against other teams. Also, the head-to-head record will not decide it if the game between them was a No result, or if they played each other twice, and won one game each.<ref>{{cite web |last1=Madhavan |first1=M. J. |title=How Net Run Rate is calculated in IPL |url=https://www.thehindubusinessline.com/news/sports/how-net-run-rate-is-calculated-in-ipl/article23941359.ece/amp/ |website=businessline |date=20 May 2018 |access-date=22 June 2019 |language=en}}</ref><ref>{{cite web |title=IPL 2019: How Net Run Rate (NRR) is calculated |url=https://cricket.yahoo.net/news/ipl-2019-net-run-rate-104520452 |website=Yahoo Cricket |access-date=22 June 2019 |date=26 March 2019}}</ref>▼
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.
▲Split teams level on points using the results from the matches between them. However, this unfairly increases the importance of that one match and reduces the importance of other matches in the league, when all matches in a league should be of equal value − the team with the better head-to-head record will have a worse record against other teams. Also, the head-to-head record will not decide it if the game between them was a No result, or if they played each other twice, and won one game each.
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.
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==References==
{{
{{Cricket statistics}}
[[Category:Cricket terminology]]
[[Category:Tie-breaking in group tournaments]]
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