Evaluating Information

The popular online encyclopedia, Wikipedia, is a great resource for general information. It is a good place to start in order to determine search terms and potentially relevant strains of thought on a given topic. However, it is not the most credible source to cite in your speech. Since anyone can update the site at any time, information may be entirely inaccurate. When using Wikipedia, look for source citations and follow the links to original source material.

The large amount of information available in your library and on the Internet can seem overwhelming. Narrow your support by evaluating the quality and credibility of each source. To determine the quality of a source, look to see whether the information provided seems comprehensive. To determine whether or not the information is comprehensive, check to see that it thoroughly covers the issue, considers competing perspectives, and cites the sources where supporting material came from.

First, check to see that your source not only discusses issues that pertain to your topic, but thoroughly explains the reasoning behind the claims it offers. Often you will already be familiar with the topic, but you will require the addition of strong reasoning to properly support your ideas. If your source cannot provide strong reasoning, it is not the best quality source. Second, determine whether the source considers competing perspectives. Debate strategists know that evidence can be found for multiple perspectives on any issue. If your source does not also recognize and consider opposing arguments, it is not the best quality source. Third, check to see that your source offers supporting data and or if it includes non-credible citations, it is not the best quality source. It is fine to use a source that is weak in one of these areas if you still find it compelling, but know that you may need to back it up with additional credible information. If the source is weak in multiple areas, do your best to avoid using it so that it does not weaken your speech.

In addition to the quality, you should examine source credibility. When evaluating credibility, focus on the sources’ qualifications, the parity of their message with similar sources, and their biases. One of the most important elements of credibility is qualification. Sometimes qualifications will be linked to a person’s profession. For example, if you are talking about earthquakes, you might want the expertise of a seismologist who studies earthquake waves and their effects. However, professional expertise is not the only type of credibility. If you want to discuss the feeling of experiencing a major earthquake, testimony from a survivor may be more credible than testimony from a scientist who studied the event but did not experience it. When examining credibility, check to see that the person has the training or experience appropriate to the type of information they offer. Next, check to see whether the information in your chosen source aligns with information in other sources on the issue. If your source is the only one that offers a particular perspective, and no other source corroborates that perspective, it is less likely to be credible.

I used to sleep nude – until the earthquake. ~ Alyssa Milano

Additionally, check for bias. All sources have bias, meaning they all come from a particular perspective. You must check to see whether the perspective of the source matches your own, and whether the perspective overwhelms the ability to offer reliable information on an issue. Also check to see whether the source is affiliated with organizations that are known to hold a particularly strong opinion concerning the issue they are speaking to.

kid on bus yawning

“Untitled” by Dmitry Ryzhkov. CC-BY-NC-SA.

In your speech, make reference to the quality and credibility of your sources. Identifying the qualifications for a source, or explaining that their ideas have been used by many other credible sources, will enhance the strength of your speech. For example, if you are giving a speech about the benefits of sleep, citing a renowned sleep expert will strengthen your argument. If you can then explain that this person’s work has been repeatedly tested and affirmed by later studies, your argument will appear even stronger. On the other hand, if you simply offer the name of your source without any explanation of who that person is, or why they ought to be believed, your argument is suspect. To offer this kind of information without disrupting the flow of your speech, you might say something like,

Mary Carskadon, Director of the Chronobiology/Sleep Research Laboratory at Bradley Hospital in Rhode Island, and Professor at the Brown University School of Medicine, explains that there are several advantages to increased amounts of sleep….Her work is supported by other researchers, like Dr. Kyla Wahlstrom at the University of Minnesota whose study demonstrated that delaying school start times increased student sleep and their performance.[1]

This sample citation bolsters credibility by offering qualifications, and identifies multiple experts who agree on this issue. You may be tempted to stop once you have found one source that supports your idea, but continuing to research and comparing the information in each source will help you better support your ideas. It will also prevent you from overlooking contradictory evidence that you need to be able to address.


  1. National Sleep Foundation. (2011). School start time and sleep. Retrieved from: http://sleepfoundation.org/sleep-news/school-start-time-and-sleep