Ran a power regression on the great retired modern era batsmen (and Alastair Cook), to predict what their "actual average" should be. To do that I took in opposition bowling quality and conditions (ICC Ranking Average), and era run scoring difficulty (era adjusted average), and multiplied those two values together, set as independent variable, and then ran a power regression. Here's the adjustments to average it spits out, and the correlation coefficient was quite strong, at over .85:
Batsman | Regression adjusted Average | Actual Average | Delta |
Brian Lara | 54.8266 | 52.88 | 1.946596 |
Kumar Sangakkara | 53.25256 | 57.4 | -4.14744 |
Viv Richards | 52.05981 | 50.23 | 1.829814 |
Javed Miandad | 51.37148 | 52.57 | -1.19852 |
Jacques Kallis | 50.947 | 55.37 | -4.423 |
Sachin Tendulkar | 50.86296 | 53.78 | -2.91704 |
Sunil Gavaskar | 50.57744 | 51.12 | -0.54256 |
Greg Chappell | 50.1509 | 53.86 | -3.7091 |
Rahul Dravid | 49.96341 | 52.31 | -2.34659 |
Allan Border | 49.56112 | 50.56 | -0.99888 |
Ricky Ponting | 49.39324 | 51.85 | -2.45676 |
Michael Hussey | 48.61139 | 51.52 | -2.90861 |
Matthew Hayden | 48.52506 | 50.73 | -2.20494 |
Shivnarine Chanderpaul | 47.22449 | 51.37 | -4.14551 |
Younis Khan | 46.92967 | 52.05 | -5.12033 |
Michael Clarke | 46.74208 | 49.1 | -2.35792 |
Adam Gilchrist | 46.24314 | 47.6 | -1.35686 |
Kevin Pietersen | 46.11968 | 47.28 | -1.16032 |
AB de Villiers | 45.66331 | 50.66 | -4.99669 |
Virender Sehwag | 45.25856 | 49.34 | -4.08144 |
Graeme Smith | 44.17528 | 48.25 | -4.07472 |
Gordon Greenidge | 43.59203 | 44.72 | -1.12797 |
Alastair Cook | 42.99906 | 45.35 | -2.35094 |
| | | |
| | | -2.38477 |
You'll note that the average delta is negative, which indicates generally that all the sub eras of the modern era were somewhat easier for batting, than the history of Test cricket as a whole.
Interesting to note though, that Lara and Viv Richards were the only positive delta players, with not many other batsmen getting particularly close. Pietersen is also one to note as having a surprisingly low negative delta for a more recent player.
Also before you ask, no I couldn't replicate this for bowlers (although I tried a couple of ways). Their performance isn't as straightforward as batsmen, because their quality is judged on more than just their simple bowling average (rightly so, i.e a performance of 1/15 and 6/90 for a match are not the same). I couldn't get a high enough correlation coefficient for me to like using it for them.