Another gauge for getting a result is "overs completed". Four-day tests are scheduled to see the total overs available reduce from 450 to 392.
Since 2000, the average number of overs required to get a result is 321; in New Zealand, it is 301.
The most average overs required are 354 in the United Arab Emirates, Pakistan's home-away-from-home since 2009.
Any bilateral tests which adopt four-dayers will be played outside the parameters of the test championship from 2019, but the statistics are worth noting.
International Cricket Council chief executive Dave Richardson said tactics and pitch deterioration will need consideration should five days meld into four.
"Stronger teams might need to use innovations such as declaring their first innings earlier, rather than batting to 500-600, to ensure there is time to win the game. It might produce more attacking cricket."
There's no lack of that in the Twenty20 era.
Richardson said the initiative came about because of a "question mark" over the sustainability of test cricket.
"We have to trial these things as a result. Is four-day cricket going to provide a better product? Who knows, but we've taken similar approaches to the introduction of technology and pink-ball tests.
"At the cricket committee [an ICC arm consisting of some of the game's luminaries], cricketers are traditional and the majority are reluctant and skeptical as to whether four-dayers are a good thing.
"But there's an acknowledgement we need to do something. Maybe this will be the catalyst to create interest in countries where test cricket is diminishing."
New Zealand Cricket's preference is to continue with the status quo.
"That is the pinnacle," chairman Greg Barclay said. "But we recognise four-day tests are a good trial and those countries developing as full members [such as test championship absentees Zimbabwe, Afghanistan and Ireland] lend themselves to four-day tests for cost and time reasons."
The first four-day "trial" test has been approved between South Africa and Zimbabwe at Port Elizabeth on Boxing Day, subject to ICC agreement on playing conditions.
Test times
In 762 cricket tests since 2000:
•Average result achieved in 4.28 days of play (New Zealand 4.24 days).
•Average result achieved in 321 overs (New Zealand 301 overs).
•41 per cent had a result before the fifth day; 35 per cent had a result on the fifth day; 24 per cent were drawn (New Zealand 40, 28 and 31 per cent respectively).
•The proposed four-day test playing conditions would reduce play from 450 to 392 overs.