McCormack Speaks

Detecting Media Bias


by Matt Braman, McCormack Graduate School student

a stack of newspapersWith “fake news” attracting so much attention in the past year, I’ve found myself questioning my own news sources much more often. While I consider this to be a normal response in an unpredictable political climate, it has also led me to consider some of the other, more subtle, ways in which news presentation might misinform us. For example, how biased is our news media currently? And if our media are biased, how does that affect our understanding of current events?

Much of the research in this area finds that while people do frequently detect bias in news reporting, often their conclusions are unsubstantiated (Baum and Groeling, 2008; Lin, Haridakis, & Hanson, 2016). In what has been coined the “hostile media” phenomenon, individuals from completely opposite ends of the political spectrum often perceive bias from the same source, even when it is objectively considered to be “relatively balanced and non-partisan” (Vallone et al., 1985 as cited in Groeling, 2013).  Unsurprisingly, this not only makes detecting bias in the media difficult, but also makes attributing such bias to journalistic intent even more challenging (Baum and Groeling, 2008). 

Types of Bias

So how do we begin to determine whether actual bias exists in our news sources, or only the mere perception of bias?  First, we must consider the different ways that bias can be expressed. Groeling (2013) and Gentzkow, Shapiro, and Stone (2014) identify two main forms. In selection bias, bias occurs naturally through the choices we make. So, for example, if we are given 3 minutes to participate in an Easter egg hunt of 5000 eggs, our selection will be limited by the number of eggs we are able to locate within that limited period of time. Since we cannot possibly collect all the 5000 eggs, the final sample we do choose can be said to represent a form of selection bias, regardless of whether it is intentional or not.

Presentation bias, by contrast, is bias that can be detected in the actual content being reported.  It can occur through either the intentional publication of misleading information or through the stylistic framing of issues around a particular ideology (Entman, 2007 as cited by Tremayne, 2015).  While the objective might be to sway readers to the left or right on political issues, however, it should be noted that more often than not the intent is not actually to deceive, but rather to appeal to the expectations of a particular audience.

This is why it is important to consider the different stakeholders that influence news media content.  On one hand, we have journalists themselves who we often assume are in the best positions to skew public opinion, but on the other hand we are also finding that audiences themselves frequently play a central role in influencing media content. Because of this, Gentzkow et al. (2014) emphasizes the importance of identifying whether bias is supply driven (internal to the firm) or demand driven (by consumers), as a tool to understand what forces might be driving a particular instance of presentation bias.

Group Dynamics

Given the increased attention on the individual’s power to influence news media content, much of the recent research in this area now focuses on how these same individuals often treat media sources similarly to how they treat in-group and outgroup members (Stroud, Muddiman, & Lee, 2014; Lin et al., 2016).  The central idea here is that the stronger an individual’s identification is with their in-group, the more likely they are to disregard information obtained from outgroup media sources (Lin et al., 2016).  Rejection of outgroups occurs not only because consumers are subject to psychological boundaries, such as selective exposure, confirmation bias, and cognitive dissonance (Tremayne, 2015), but also because there is a tendency to view outgroup members as nondiverse and homogenous, making them easier to reject (Tajfel and Turner, 1979 and Turner, 1999 as cited in Stroud et al., 2014).

In line with this, research has also begun to consider whether affiliation with a particular political party might inadvertently fuel bias in news media content as well. In fact, Baum et al. (2015), Levendusky (2013), and Stroud (2010) all find support for this theory, arguing that exposure to partisan media can lead to greater polarization of thought, which is reflected in our media choices as well.

This finding is telling in that it reveals that not only can individuals fuel presentation bias in the media, but also that the media outlet will often serve to reinforce, or even make more extreme, the in-group that contributed to presentation bias in the first place. Accordingly, “partisan media cause, or at least exacerbate, polarization” (Baum, de Benedictis-Kessner, Berinsky & Yamamoto, 2015).  While it is natural for us to ally ourselves with like-minded individuals, the cost of that power might be that we are less informed about important issues than we should be. News media outlets, through a sustainable business model, can simply ensure their success by catering to the needs of their dedicated readers, and occasionally delivering party lines.

A Way Forward

As Tremayne (2015) succinctly states, “[d]ialogue across ideological groups is decisive to a functional democracy.” Unfortunately, it seems as if our attitudes are becoming more polarized, not less, making compromise extremely difficult in modern times.

I have to admit that when I first delved into this area, I didn’t expect to learn that individuals are actually one of the biggest forces contributing to bias in the news media, not journalists.  I also find it incredibly difficult to consider, let alone acknowledge, that group memberships, such as the political party we identify with, might actually be causing our society to be less informed about important issues, not more.

But it does make sense to me. One of my biggest frustrations with the fake news debate has been that it seems to have done little to cause people to question their own sources of information. Instead, most people seem to believe that fake news is easy to detect and a problem of their opposite political party, not their own. More likely than not, however, the forces that drive fake news content are probably not all that different from those that drive bias in the news media.

So how do we fix it?  While it may sound like a controversial idea, I would argue that we are obligated to seek out, and consume, media that contradicts our notion of right and wrong. In other words, since self-selection of media is instrumental in fueling bias, to counter it we must find a way to disrupt the selection process. Accordingly, it is my hope that by choosing media sources we are normally averse to, we will not only gain information about how our ideology holds up under a new lens, but also we might discover that some outgroup ideas are not as radical as we previously thought.


Baum, M.; de Benedictis-Kessner, J.; Berinsky, A.; Knox, D., & Yamamoto, T.  (2015). Disentangling the causes and effects of partisan media choice in a polarized environment: Research to date and a way forward [DRAFT].

Baum, M.A.; Groeling, T. (2008). New media and the polarization of American political discourse.” Political Communication. 25, 345-365.

Gentzkow, M.; Shapiro, J.M.; Stone, D.F. (2014). Media bias in the marketplace: Theory. Handbook of Media Economics. Anderson, S.; Strömberg, D; & Waldfogel, J. (Eds.). Atlanta: Elsevier Inc.

Groeling, T. (2013). Media bias by the numbers: Challenges and opportunities in the empirical study of partisan news.” Annual Reviews in Political Science. 16:129-151.

Levendusky, M.S. (2013). Why do partisan media polarize viewers?” American Journal of Political Science. 57(3):611-623.

Lin, M.C.; Haridakis, P.M.; & Hanson, G. (2016). The role of political identity and media selection on perceptions of hostile media bias during the 2012 presidential campaign. Journal of Broadcasting & Electronic Media. 60(3):425-447.

Stroud, N.J.; Muddiman, A.; & Lee, J.K. (2014). Seeing media as group members: An Evaluation of partisan bias perceptions. Journal of Communication. 64:874-894.

Tremayne, M. (2015). Partisan media and political poll coverage. Journal of Information Technology & Politics. 12:278-284.


Matthew Braman studies public administration at the John W. McCormack Graduate School of Policy and Global Studies. He wrote this blog as part of his New England Political Environment course taught by Professor Christine Thurlow Brenner.







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