Run-a-Ball Difference was the original name, but the acronym (RABD) isn’t very mouth-friendly. DRAB sits better, in one’s gob, and adds a touch of irony.
WHAT IS IT THEN?
In T20 cricket, and other limited overs contests, run-rates and required run-rates can be a little deceptive. In 50 over cricket, in particular, the required run-rate appears to react very sluggishly to developments in the game. In T20 cricket, the same is true at the start of the innings, so the progress (or otherwise) of your team can be difficult to ascertain.
DRAB IN ACTION … http://www.birdfolk.co.uk/cricmob
IN SHORT – the more this number climbs, the better your team is doing. If it drops, or becomes negative, progress is being checked.
I propose a simple statistical alternative: the “run-a-ball difference”. In all limited overs cricket the idea of scoring at a run-a-ball has long been something of a benchmark – while 120 represents a poor score in T20, 300 has long been the sign of a good score in ODIs. Observing the difference between a team’s current score and the score that they would have had they scored at a run-a-ball is a useful way to judge your team’s progress.
For example, when setting a score, your team has 60 from the first 8 overs – a run-rate of 7.5 per over. This equates to +12 using the “run-a-ball difference”. 8 overs at a run-a-ball is 48 runs so, with 60 runs, the team are 12 ahead of that. Say they score 20 off the next 2 overs, reaching 80 from 10, a run-rate of 8 .. that doesn’t sound like a terribly big increase, but in terms of the run-a-ball difference, they have from from +12 to +20, perhaps illustrating the improvement in a more tangible fashion.
One may apply run-a-ball difference slightly differently when a team is chasing a score: for example your opponents have made 175. At the beginning of the chase, the run-a-ball difference is 55 … a run-a-ball provides 120 and your team needs to find an “extra” 55 runs. A few overs go by and your team is 60 from 8 with 115 runs still required from 72 balls – a run-rate of 7.5 and a required run-rate of 9.6. Looking alone at either the 7.5 or the 9.6, it can be hard to know how your team is doing, but run-a-ball difference is now 43 (115 runs required minus 72 balls left). The fact that 43 is a fair chunk less than the initial 55, helps me understand that progress is being made.