June 23, 2017

Has the extra outfielder affected scoring rates in the last ten?

A comparison of the numbers in the last ten overs of ODIs before and after the rule change which allows an extra fielder outside the circle in the last ten overs

In the 2017 Champions Trophy, the scoring rates in the last ten overs for teams batting first was much lower than in the 2015 World Cup © ESPNcricinfo Ltd

The 2017 Champions Trophy was the second global ODI tournament ever in which the average scoring rate exceeded 5.5 runs per over; the first had been the 2015 World Cup, when teams scored at 5.65 runs per over, compared to 5.54 in this Champions Trophy.

These run rates only indicate the increasing dominance of bat over ball in ODI cricket in the last few years, but the patterns of scoring in these two tournaments were quite different: in the World Cup, the teams batting first scored at only 4.3 runs per over in the first ten overs, but went into overdrive in the last ten, scoring at 9.32. In the Champions Trophy, teams batting first scored at 4.79 in the first ten, but in the last ten the rate was only 7.18. (Only first innings has been considered, as the scoring patterns of chasing teams often depend on the target in front of them; in the 2015 World Cup, teams chasing scored only 6.68 in the last ten, while in the Champions Trophy it climbed to 8.79.)

Several times in the Champions Trophy, teams which were reasonably well-placed after 40 came unstuck when they tried to accelerate in the last ten. Australia managed only 57 in these overs against England after being 220 for 4 at the end of 40; Bangladesh got exactly as many against India, while South Africa got 63 against Pakistan.

The numbers in the middle overs (11th to 40th) weren't too different - the run rate was 5.34 in the World Cup, and 5.25 in the Champions Trophy - which have led to suggestions that the change in fielding regulations could have led to the fall in scoring rates in the last ten. During the 2015 World Cup, only four fielders had been allowed outside the circle in the non-Powerplay overs, but from July 2015, an extra fielder had been permitted outside the circle in the last ten. Has that made a difference to the scoring rates, brought bowlers back into the contest? The Champions Trophy itself is small a sample size to draw conclusions from, so let's look at all ODIs since the rule change, and compare with a similar number of ODIs before the rule change.

Since the five-fielder rule was introduced in July 2015, 233 ODIs have been played (of which 11 were not completed), while in the period between January 2014 and June 2015, 211 games were played (including seven no-results). That seems a fair period for comparison, to see if ODIs over these two periods have witnessed huge changes in scoring rates and scoring patterns.

First, the overall numbers. In the 18 months between January 2014 and June 2015, teams scored 5.44 runs per over and 32.43 per wicket. From July 2015 onwards, the rate has dropped marginally - by about 1.5% - to 5.36, while the average runs per wicket is 31.88. For teams batting first, the drop is equally marginal, from 5.55 to 5.44 (2%). There was a perception that the earlier restriction of four fielders outside in the last ten was aiding teams batting first rack up really huge scores (as was the case in the 2015 World Cup), but the overall numbers during this period point in the opposite direction, with teams batting first having a 101-102 win-loss record in the previous period, and 116-104 in the period since July 2015.

ODI stats, before and since the rule change
Period Ave Run rate
 Jan '14 to Jun '15  32.43  5.44
 Jul '15 onwards  31.88  5.36
Teams batting 1st in ODIs, before and since the rule change
Period Ave Run rate W/L Ratio
 Jan '14 to Jun '15  34.12  5.55  101/102  0.99
 Jul '15 onwards  32.60  5.44  116/104  1.115

In the last ten overs, though, the change in rates is slightly more perceptible: from 8.39 in the earlier period to 7.76 in the last couple of years (in the first innings of ODIs). In matches between the top nine teams, those rates change to 8.49 and 7.94, still a drop of around 6.5%.

The frequency of boundaries has reduced by 22% since the extra fielder has been allowed outside the circle in the last ten © ESPNcricinfo Ltd

The bigger difference is in the balls-per-boundary stat: in the period between January 2014 and June 2015, there was a boundary hit every 6.2 balls during the last ten overs; in the period since the rule change, the frequency has reduced to one boundary every 7.57 balls. That is a change of 22%, which is a far greater difference than the run-rate numbers. The percentage of runs in boundaries has reduced from 53% to 47%, a drop of 11% (or six percentage points). So clearly, some of the runs lost in boundaries have been compensated for by runs in singles, twos and threes, but there has still been a small drop in run rate. The difference, though, is nowhere near what was seen in the two global tournaments in this period.

The extra fielder outside the circle in the last ten was always likely to benefit the spinner - especially when batsmen were looking for quick runs - and so it has proved. Since July 2015, spinners' average has improved by nearly 24%, while the economy rate has improved by about 11%. Rashid Khan has led the cause of the spinners during this period, taking 11 wickets at an economy rate 5.04.

Spinners have clearly benefited from the presence of an extra outfielder in the last ten overs © ESPNcricinfo Ltd

In ODIs between the top nine teams, New Zealand had the best run rate and average in the last ten in the 2014-15 period, but since the rule change they have plummeted to near the bottom (in matches between teams in the top nine). India and England are the two teams which have improved the most in the last ten. In England's case, especially, their change in personnel and attitude has been so significant since the 2015 World Cup that one extra fielder in the outfield hasn't really affected their aggression.

Run rate diff for batting teams before and since the rule change*
Team 2014-15 RR Jul '15-RR RR diff
 Pakistan  6.53  7.48  0.95
 England  7.94  8.75  0.81
 India  8.40  9.15  0.75
 Australia  8.70  8.86  0.16
 Bangladesh  7.88  7.20  -0.68
 South Africa  9.28  8.12  -1.16
 Sri Lanka  8.52  6.84  -1.68
 West Indies  9.10  7.10  -2.00
 New Zealand  9.45  7.13  -2.32
* When batting first, in ODIs between the top 9 teams only

S Rajesh is stats editor of ESPNcricinfo. @rajeshstats