Unsurprisingly, bowling of that pace matched with that level of relentlessly hitting a good line and length, has produced an exceptionally high level of threat. By CricViz’s Expected Averages measure, the deliveries Australia have bowled this series would (had they been bowled to a typical Test batsman) have averaged 23.5 - that’s the lowest Expected Average for any team in a Test series (of three matches or more) since 2006, when records began.
The model is built on historical ball-tracking data, going back to 2006, assessing a huge range of features on every delivery, including the simple facts of line, length, and speed, to more granular details like swing and seam movement, dip, bounce, release point and plenty more. What the model aims to do is to divorce the quality of the batting, from the bowling; for coaches and pundits, being able to distinguish between a ‘good’ 2-60 and a ‘bad’ 3-40 is valuable.