graber 2002
scientists fail to show media effects (but they're there)

zaller 2002
power analysis needed to find aggregate effects that may be hidden under the surface

price & zaller 1993
reliance on self-reported levels of news media should be abandoned; using more types of media should expose more effects

graber 2002
efforts hampered by measurement problems; cognitions, feelings, and actions of respondents are difficult to seperate from actual effects that may have changed