Bias by omission – leaving one side out of an article, or a series of articles over a period of time; ignoring facts that tend to disprove liberal or conservative claims, or that support liberal or conservative beliefs; bias by omission can occur either within a story, or over the long term as a particular news outlet reports one set of events, but not another. To find instances of bias by omission, be aware of the conservative and liberal perspectives on current issues. See if both the conservative and liberal perspectives are included in stories on a particular event or policy.
Bias by selection of sources – including more sources that support one view over another. This bias can also be seen when a reporter uses such phrases as “experts believe”, “observers say,” or “most people believe”. Experts in news stories are like expert witnesses in trials. If you know whether the defense or the prosecution called a particular expert witness to the stand, you know which way the witness will testify. And when a news story only presents one side, it is obviously the side the reporter supports. (Journalists often go looking for quotes to fit their favorite argument into a news story.) To find bias by use of experts or sources, stay alert to the affiliations and political perspective of those quoted as experts or authorities in news stories. Not all stories will include experts, but in those that do, make sure about an equal number of conservatives and liberals are quoted. If a story quotes non-experts, such as those portrayed as average citizens, check to be sure that about an equal number come from both sides of the issue in question.
Bias by story selection – a pattern of highlighting news stories that coincide with the agenda of either the Left or the Right, while ignoring stories that coincide with the opposing view; printing a story or study released by a liberal or conservative group but ignoring studies on the same or similar topics released by the opposing group. To identify bias by story selection you’ll need to know the conservative and liberal sides of the issue. See how much coverage conservative issues get compared to issues on the liberal agenda, or liberals compared to conservatives. For example, if a liberal group puts out a study proving a liberal point, look at how much coverage it got compared to a conservative study issued a few days or weeks earlier, or vice versa. If charges of impropriety are leveled at two politicians of approximately equal power, one liberal and one conservative, compare the amount of coverage given to each.
Bias by placement – Story placement is a measure of how important the editor considers the story. Studies have shown that, in the case of the average newspaper reader and the average news story, most people read only the headline. Bias by placement is where in the paper or in an article a story or event is printed; a pattern of placing news stories so as to downplay information supportive of either conservative views or liberal views. To locate examples of bias by placement, observe where a newspaper places political stories. Or whenever you read a story, see how far into the story each viewpoint first appears. In a fair and balanced story, the reporter would quote or summarize the liberal and conservative view at about the same place in the story. If not, you’ve found bias by placement.
Bias by labeling — Bias by labeling comes in two forms. The first is the tagging of conservative politicians and groups with extreme labels while leaving liberal politicians and groups unlabeled or with more mild labels, or vice versa. The second kind of bias by labeling occurs when a reporter not only fails to identify a liberal as a liberal or a conservative as a conservative, but describes the person or group with positive labels, such as “an expert” or “independent consumer group”. In so doing, the reporter imparts an air of authority that the source does not deserve. If the “expert” is properly called a “conservative” or a “liberal” the news consumer can take that ideological slant into account when evaluating the accuracy of an assertion. When looking for bias by labeling, remember that not all labeling is biased or wrong. Bias by labeling is present when the story labels the conservative but not the liberal, or the liberal but not the conservative; when the story uses more extreme sounding labels for the conservative than the liberal (“ultra-conservative”, “far right”, but just “liberal” instead of “far left” and “ultra-liberal”) or for the liberal than the conservative (“ultra-liberal”, “far left”, but just “conservative” instead of “far right” and ”ultra-conservative ; and when the story misleadingly identifies a liberal or conservative official or group as an expert or independent watchdog organization.
Bias by spin – Bias by spin occurs when the story has only one interpretation of an event or policy, to the exclusion of the other; spin involves tone – it’s a reporter’s subjective comments about objective facts; makes one side’s ideological perspective look better than another. To check if it’s spin, observe which interpretation of an event or policy a news story matches – the liberal or conservative. Many news stories do not reflect a particular spin. Others summarize the spin put on an event by both sides. But if a story reflects one to the exclusion of the other, then you’ve found bias by spin.
The above information is excerpted and adapted from How to Identify Liberal Media Bias by Brent H. Baker, Vice President for Research and Publications at Media Research Center.