The correlation between Cost and Win Rate is 0.72. The more Cost, 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 Cost (blue dots) with respect to the expected value (red line).
Efficiency
Boots Of Travel 0.1125
Moon Shard 0.1098
Holy Locket 0.0927
Boots Of Travel 2 0.0915
Aghanim'S Shard 0.0890
Butterfly 0.0797
Assault Cuirass 0.0757
Vladmir'S Offering 0.0752
Boots Of Bearing 0.0726
Pavise 0.0618
Yasha And Kaya 0.0604
Heart Of Tarrasque 0.0576
Aeon Disk 0.0561
Satanic 0.0560
Meteor Hammer 0.0557
Eye Of Skadi 0.0556
Solar Crest 0.0549
Octarine Core 0.0539
Shiva'S Guard 0.0536
Overwhelming Blink 0.0452
Revenant'S Brooch 0.0415
Veil Of Discord 0.0391
Swift Blink 0.0376
Phylactery 0.0369
Magic Wand 0.0360
Bloodstone 0.0339
Nullifier 0.0329
Linken'S Sphere 0.0298
Aether Lens 0.0297
Pipe Of Insight 0.0296
Harpoon 0.0261
Aghanim'S Scepter 0.0257
Bottle 0.0255
Disperser 0.0253
Soul Ring 0.0251
Lotus Orb 0.0250
Sange And Yasha 0.0241
Guardian Greaves 0.0240
Refresher Orb 0.0231
Kaya And Sange 0.0231
Daedalus 0.0212
Bracer 0.0209
Power Treads 0.0193
Orb Of Corrosion 0.0186
Null Talisman 0.0174
Glimmer Cape 0.0172
Crimson Guard 0.0166
Abyssal Blade 0.0157
Phase Boots 0.0141
Spirit Vessel 0.0123
Wind Waker 0.0105
Scythe Of Vyse 0.0100
Wraith Band 0.0082
Tranquil Boots 0.0071
Eternal Shroud 0.0056
Blade Mail 0.0048
Bloodthorn 0.0046
Blink Dagger 0.0040
Desolator 0.0013
Arcane Blink -0.0002
Force Staff -0.0007
Falcon Blade -0.0010
Ethereal Blade -0.0024
Eul'S Scepter Of Divinity -0.0030
Hurricane Pike -0.0032
Skull Basher -0.0036
Aghanim'S Blessing -0.0061
Manta Style -0.0067
Arcane Boots -0.0072
Witch Blade -0.0080
Rod Of Atos -0.0163
Heaven'S Halberd -0.0170
Mage Slayer -0.0211
Mjollnir -0.0216
Armlet Of Mordiggian -0.0239
Drum Of Endurance -0.0269
Diffusal Blade -0.0278
Monkey King Bar -0.0289
Radiance -0.0331
Dragon Lance -0.0365
Urn Of Shadows -0.0386
Gleipnir -0.0430
Mask Of Madness -0.0445
Black King Bar -0.0457
Hand Of Midas -0.0491
Silver Edge -0.0543
Vanguard -0.0631
Orchid Malevolence -0.0700
Battle Fury -0.0732
Echo Sabre -0.0745
Mekansm -0.0762
Dagon (5) -0.0806
Crystalys -0.0821
Medallion Of Courage -0.0867
Helm Of The Overlord -0.0895
Dagon -0.1106
Helm Of The Dominator -0.1205
Shadow Blade -0.1405
Dagon (4) -0.1430
Dagon (2) -0.1444
Dagon (3) -0.1476
Maelstrom -0.1601