When pressing Alt and hovering items, the range of affixes is shown. In case of the affix “Ward gained on the use of Shift”, the range seems wrong.
Example 1: Rogue Armor, Tier 4
Range: 4650% - 6000%
Example 2: Idol, Tier 1
Range: 1139% - 3015%
Unfortunately, I cannot show a screenshot, as it does not work while pressing Alt. So you just have to believe me