The Cardinal has complained of a "subtle anti-Catholic bias at work" in this matter.

C1 Coin-tossing computers found to show subtle bias.

Other subtler biases were addressed, as details about hair color and clothing began to fade from stories about women.

Nor was this the only subtle and half-conscious bias which shaped this great collection.

Unknown to them the unused word gives their minds a subtle bias.

Are you talking about a subtle bias against Animals, interwoven into early unionist tracts, and still in operation today?

Clearly, outright deception is a simpler concept than subtle bias.

Black students spoke of subtle bias and condescension.

Some European players have quietly complained about subtle bias against them.

And what they found was a subtle bias that went away when the umpires thought someone was watching them.