Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
This paper defines the power of a media organization as its ability to induce voters to make electoral decisions they would not make if reporting were unbiased. It derives a robust upper bound to media power over a range of assumptions about the beliefs and attention patterns of voters. The paper then presents estimates of the power index for the United States and shows how these can inform merger analysis and other policy debates.