How Effective is Steel Shot?

Is steel a more than effective option for upland bird hunting? Before anyone spins this story into something it is not: lead is more effective than steel. I will not claim otherwise. But, the efficacy gaps we have come to believe are infinitely smaller than we think and, in my opinion, insignificant in the discussion of lethality for upland game. Scientists have looked into everything from killing efficiency to the impact of steel on shot patterns. As we will find, the story we have been told does not match up with what research has shown.