The correlation between kda and Win Rate is 0.85. The more kda, the more Win Rate, and vice versa. But some values are higher than expected, some are lower. Efficiency is a difference between the value of Win Rate depending on kda (blue dots) with respect to the expected value (red line).
Efficiency
Book Of The Dead 0.0520
Stormcrafter 0.0436
Telescope 0.0429
Arcanist'S Armor 0.0395
Ceremonial Robe 0.0235
Arcane Ring 0.0214
Timeless Relic 0.0201
Ascetic'S Cap 0.0193
Giant'S Ring 0.0193
Trusty Shovel 0.0182
Spell Prism 0.0166
Seeds Of Serenity 0.0142
Bullwhip 0.0120
Martyr'S Plate 0.0106
Psychic Headband 0.0092
Dandelion Amulet 0.0067
Seer Stone 0.0063
Quickening Charm 0.0061
Havoc Hammer 0.0057
Eye Of The Vizier 0.0056
Occult Bracelet 0.0032
Faded Broach 0.0022
Defiant Shell 0.0017
Cloak Of Flames 0.0016
Force Boots -0.0007
Tumbler'S Toy -0.0020
Book Of Shadows -0.0024
Fairy'S Trinket -0.0026
Gossamer Cape -0.0044
Apex -0.0046
Fallen Sky -0.0060
Mirror Shield -0.0070
Pig Pole -0.0071
Mind Breaker -0.0076
Lance Of Pursuit -0.0078
Philosopher'S Stone -0.0078
Trickster Cloak -0.0080
Ninja Gear -0.0083
Stygian Desolator -0.0086
Penta-Edged Sword -0.0095
Pirate Hat -0.0104
Dragon Scale -0.0107
Vampire Fangs -0.0140
Ring Of Aquila -0.0149
Pupil'S Gift -0.0155
Spark Of Courage -0.0161
Grove Bow -0.0165
Ogre Seal Totem -0.0170
Broom Handle -0.0186
Paladin Sword -0.0188
Enchanted Quiver -0.0205
Vambrace -0.0206
Titan Sliver -0.0244
Elven Tunic -0.0284
Ex Machina -0.0302
Duelist Gloves -0.0303