Test matches are finishing sooner. In the 1970s, 77.65% of Tests reached day five; in the 2020s, the figure is 41.43%. The share finishing in two or three days has risen from 2.79% to 23.11%.

The ball-count data point in the same direction. In the six seasons before the World Test Championship, the average Test used 1,946.64 deliveries, or about 324.4 overs. In the 2023–25 WTC cycle, the average was 1,638.09 deliveries, roughly 273 overs.

Faster scoring and more wickets

The six pre-WTC seasons ran at 3.23 an over, with a wicket every 59.52 balls. In the 2023–25 cycle, scoring rose to 3.65 an over and a wicket fell every 47.81 balls.

That combination shortens matches from both directions: batting moves the game on faster and bowling sides take 20 wickets more quickly.

There is no single explanation

T20 has changed batting, but it is not the whole story. A study of 667 Tests involving the leading eight nations between 2000 and 2020 found more runs in sixes, fewer in fours and a steep fall in draws. Across that sample, average run rates stayed between 3.1 and 3.3 and average match length moved from 4.5 days to 4.3.

DRS changes individual decisions, but it does not by itself explain a Test ending on day three. The broader change is a combination of faster batting, more attacking bowling and a World Test Championship that awards 12 points for a win and four for a draw.

The value of a fifth day

The average 2023–25 WTC match used about 273 overs; a proposed four-day Test at 98 overs a day would schedule 392. That average is not a reason to set the format around the most typical match.

In that WTC cycle, all four draws were heavily affected by rain, with more than 300 overs lost between them. A fifth day allows a match to recover from weather, a long rearguard, a slow-changing surface or a first innings that needs time to develop.