Quarterly Journal of Political Science > Vol 6 > Issue 1

Shifting Ideologies? Re-examining Media Bias

John T. Gasper, Visiting Assistant Professor of Political Science, Carnegie Mellon University in Qatar, USA, gasper@andrew.cmu.edu
Suggested Citation
John T. Gasper (2011), "Shifting Ideologies? Re-examining Media Bias", Quarterly Journal of Political Science: Vol. 6: No. 1, pp 85-102. http://dx.doi.org/10.1561/100.00010006

Publication Date: 23 Aug 2011
© 2011 J. T. Gasper
Public opinion,  Interest groups


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In this article:
The Data and Model 
Structural Model 


This research note engages the current research on measuring media bias. I present a reanalysis of the results found in Groseclose and Milyo (2005) and show that the original parameter estimates of the ideological positions of media outlets are not stable over time. Using the same data but analyzed over different periods of time, I find a different conclusion than the previous article. I examine four-year rolling time periods and find that the data produce different parameter estimates in the early- to mid-1990s as compared to after 2000, with all analyzed outlets appearing more moderate or conservative in later time periods. My results indicate that the estimated positions are sensitive observations in the data and the time period of observation of the outlet.

An erratum for this article can be found on the Accompanying Work tab



Quarterly Journal of Political Science, Volume 6, Issue 1 10.1561/100.00010006_err