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The Need to Think Critically

Information is now easily available, but it’s hard to discern what is true. You must be able to evaluate the information you encounter and decide whether or not it’s worth absorbing. This means being able to evaluate words and numbers, as well as identifying misinformation.

Numbers

When you encounter numbers, remember that they are based on the decisions of people. These people decided what to count and how to count them. They also decided how to record their counting and then generate statistics from it. Therefore, no matter how authoritative a number may seem, it isn’t fact but rather an interpretation of reality by those who created it. When someone offers a numerical claim, check its data for plausibility. If a price dropped more than 100%, the store would be paying you to take it! Also keep in mind that percentage increases or decreases have different meanings depending on whether they’re going up or down (e.g., if interest rates go from 3% to 4%, this is a 33% increase).

Averages are important because they communicate information. The most common number in a group is the mode, which comes from adding all the items and dividing by the number of items. Adding everything up and then dividing it by how many there were gives you the mean. The median is when you put all of them in order, like a list, and take out the middle one.

Graphs

Your brain evolved to see patterns in things. However, it’s easier for people to interpret data when presented visually (graphically). When you present data graphically, you have opportunities to misrepresent information or misinterpret the meaning of that information. For example, if a report shows sales figures in table format instead of as a chart or graph, it will be more accurate than if they’re represented on a chart or graph. If your company is selling soft drinks and you want to show how well your product is doing with consumers, don’t just show them the numbers; put those numbers into context by using an appropriate scale and axis.

When you put two unrelated things on a graph, it can be misleading. For example, if the height of a weed is measured at four inches one day and six inches another day, people might think that it was five inches high in between those days. However, when extrapolating this data over time to predict how tall the plant will be in the future, other factors must be considered because growth rates are not linear or constant.

Statistics and Samples

Even though statistics are precise, they can be misinterpreted. For example, if you say that a certain number of people have access to something—say health care or cellphones—it might sound impressive. But it’s possible that the actual numbers of those who use these services is much smaller than the number who have access to them. It’s better to look at proportions rather than specific numbers when analyzing data.

There are some numbers that prove to be invalid because the sources were not collected properly. A number of samples can give you accurate information, but only if they’re large enough and representative of the population you’re studying. If your sample is biased in any way, then it’s hard to draw any conclusions from it. People who care about an issue are more likely to take part in a study about it, so “reporting bias” is something to be aware of when dealing with surveys or polls. Misinterpretation happens all the time when people answer questions incorrectly or don’t understand what’s being asked of them. When evaluating statistical claims, look for weaknesses in data collection and possible biases in sampling or defining terms.