Dear Data Doctor, You probably saw this in the news the other day, that ice cream sales are linked to the number of East Coast hurricanes. And now all of my friends are talking about boycotting ice cream to help the East Coast. I don’t think giving up ice cream is the answer, but numbers don’t lie, right? Signed, Frozen in Indecision
Dear Frozen,
It is great that you and your friends want to do your part and are willing to make drastic changes, but you’re right that giving up ice cream isn’t the answer. Humans like simple explanations, so when there is a demonstrated link or connection between two things, we assume that one must cause the other to happen, similar to what your friends assumed about the ice cream sales and East Coast hurricanes. But did you know that there are plenty of links between things that are purely coincidental? For example, there is a link between the divorce rate in Maine and the per capita consumption of margarine. Or the number of movies Nicholas Cage has been in and the number of people who drowned by falling into a swimming pool. These links, while true according to the data, don’t mean that margarine is causing divorce or Nicholas Cage movies are causing people to drown by falling into a swimming pool. Rather, they are random connections that occasionally happen in life and there are many, many other factors involved. A phrase common in my world is “correlation does not equal causation,” which means just because there is a link between two things doesn’t mean one causes the other. So for now, be free and enjoy your ice cream!
My friend told me that as the number of hours a student sleeps decreases, so do their math test scores. (Which I could have guessed). But then they said that indicates a positive link between the number of hours sleeping and math test scores and now I’m confused! How can something that is not good be positive? Please help. Signed, Positively Confused
Dear Positively Confused, Don’t panic, and let’s see if we can neutralize your confusion. When we use the words “positive” and “negative”, we often use them to describe something good or bad. For example, eating ice cream is a positive experience or I just got negative feedback on my paper. But when talking about the link or relationship between two things (also called variables), positive and negative take on a different meaning.
A positive link, or relationship, means that the two things are moving in the same direction, whether it is up or down. For example, as the number of hours a student sleeps increases, so do their math test scores.
On the other hand, a negative link, or relationship, means that the two things are moving in the opposite direction. For example, as the amount of anxiety a student feels decreases, their math test scores increase.
I was sitting around in the break room the other day eating my lunch and my co-workers were talking about spending habits. One person suggested that the more money you spend, the less money you’ll have, but someone else said that’s a weak connection and they started bickering back and forth. I quickly swallowed my lunch and got out of there before they drew me into their argument. But I can’t get it out of my head. It seems logical that spending more money would make you have less money, so I don’t know what my one co-worker meant by a “weak connection”. Please explain. Signed, Tired from this Mental Lift
Dear Tired, I’m sorry this has preoccupied your mind and hopefully this explanation will help. In the data world, saying that a connection is “strong” or “weak” has nothing to do with how logical we think something is, but more about how close the relationship is. A strong connection indicates that a change in one thing would mean a change in another. But a weak connection would suggest that a change in one thing may not mean a change in another. In the case of the conversation you overheard at work, let’s think about what happens when you spend more money. Yes, most of the time that means your bank account drops (at least for me it does). But is it possible other factors may contribute to that change? I could spend money but also get money in the same day. So my bank account could stay the same or even increase. Or what if you spent money on something that is an investment like stocks or a house? As you can see, your co-worker was probably thinking of the many other factors that make the connection between spending money and having less money weaker. Hopefully, this puts your mind at rest!
*All correspondence is completely fictional and created entirely for this blog post.
About the Author
Dr. Megan Mikesell is a Program Manager with The EdVenture Group. Megan completed her doctoral program at West Virginia University (WVU) focusing on Human Development and Family Studies, specifically on early childhood educators’ attitudes toward addiction and how it relates to their relationships with students.
Prior to joining The EdVenture Group, Megan worked as the program coordinator for Project TRAIN (Teacher Resources for Addiction Impact Now), an initiative at WVU that seeks to meet WV K-12 teachers’ expressed needs regarding the impact of the opioid crisis. Megan is excited to bring her human development expertise to work with a passionate, like-minded team whose primary goal is to support families, schools and communities for a safer and healthier future.
