S Rajesh is stats editor of ESPNcricinfo. @rajeshstats
Since their 3-1 series triumph in Australia in 2010-11, England have lost nine out of 10 Tests in the country, averaged 25 with the bat, and nearly 46 with the ball. That is the sort of recent history England will be up against over the next few weeks, as they try to regain the Ashes.
Australia have been battling problems of their own recently, and lost their last home series, against India. However, their overall win-loss record in the last 10 years is still an impressive 36-8, with 11 series wins out of 16; they have lost twice each to India and South Africa, and drew a series against New Zealand in 2011-12. In fact, South Africa and India have been the two teams which have competed strongly in Australia. South Africa have a 3-1 win-loss record and are the only overseas team to score more runs per wicket than they concede in Australia in this period, while India's record is marred by their hopeless 4-0 drubbing in 2011-12.
Smith, Warner vs Anderson, Broad
James Anderson will play his fifth Test series in Australia, and Stuart Broad his fourth. How they go against Australia's line-up in their home conditions could be a key component of which way the series pans out. Of particular interest will be their battles against Steven Smith and David Warner, the two giants of Australia's batting.
Broad was dominant against Warner in the 2019 Ashes series in England, dismissing him seven times while conceding just 35 runs, an average of five runs per dismissal. However, the last time they played in Australia, Warner scored 73 off 175 deliveries from Broad without being dismissed.
Overall, both Anderson and Broad have dominated Warner in England, but Warner averages more than 50 against each of them in home conditions. Smith's numbers against them have a remarkable symmetry - his average against Anderson in England is his average against Broad in Australia, and vice-versa. In Australia, Anderson has had more success against him, though Smith still averages a healthy 45.2.
Red-hot Root's century mission
Joe Root's average in Australia is a modest 38 from nine Tests, but the last time he toured there - in 2017-18 - he did much better, averaging 47.25, and scoring five fifties from nine innings. A century eluded him, though, which means his highest score from 17 Test innings in Australia is 87. It is the only country where he has played at least 10 innings without a hundred. Australia will be happy if those stats still hold true at the end of this series.
However, Root and Test centuries have had a strong bonding in 2021 - he has scored six of them, which is twice his previous best in any calendar year. That suggests he should end his century drought in Australia this time around, and also lift his overall Test average in the country to beyond 40.
Going by his numbers against Australia's current bowlers, his biggest threat will be his opposite number, the newly appointed captain Pat Cummins. Cummins has had the better of Root both in England and Australia. Against Josh Hazlewood, Mitchell Starc and Nathan Lyon, Root averages more than 45 in Australia.
However, apart from Root, England will also need the rest of the top order to score big runs. Among the batters who have played in Australia, only Dawid Malan averages over 40. Malan was impressive on the tour in 2017-18, scoring a century and three fifties in nine innings.
Australia's pace advantage
On the last two tours, England's fast bowlers have struggled in Australia: they have averaged 38.56 runs per wicket, compared to the home fast bowlers' average of 25.73 in the period since November 2011. The only country where they have a poorer average in these 10 years is in India (41.85).
The Kookaburra hasn't been a friend for England's pace bowlers: Anderson (35.43) and Broad (37.17) both average over 35 here, while Chris Woakes' 10 wickets have cost him 49.50 each. Ben Stokes has done better, averaging 32.80, but England will want more from their frontline fast bowlers this time around. They'll hope that Mark Wood's pace, and Ollie Robinson's accuracy and ability to extract bounce, will change the narrative this time around.
Spin problems in Australia
If England's fast bowlers have underwhelming records in Australia, then the spinners have been an embarrassment in the last two series, taking 22 wickets in 10 Tests at an average of 87. Except for Scott Borthwick, who picked up 4 for 82 in the last Test of the 2013-14 series, no England spinner averages less than 80 in Australia during this period. That underlines the challenge before Jack Leach and Dom Bess - should they play - as England try to emulate their achievement of 2010-11.