Anecdotes, Correlation and Causation–Exercise One

Read the questions at the end first then read the dialogue immediately below as you look for answers to the questions. Answer the questions using full sentences and correct spelling and grammar. Be as brief and direct as possible. Remember to be clear, correct, and complete.

Three friends, all little league coaches, were talking about hitting. The following is a transcript of their conversation.

(Note:  For this exercise, you may cut and paste your answers from the conversation below.)

SARAH: Look, it’s obvious; it’s just natural talent. Some kids have it and some kids don’t. I don’t have to do any research or testing. I just know.

PATRICIA: I think the visualization exercises I do with my team work. I have them close their eyes and I walk them through, step-by-step, as they imagine getting a hit.

DELA: Well let’s check. I have all the stats from the last three seasons on my laptop right here.

SARAH: Okay, how do we want to define good “hitting,” batting average, number of home runs?

PATRICIA: Let’s do batting average.

DELA: Okay. Patricia, for the last three seasons, have you done the visualization exercises with all your players?

PATRICIA: Yes. I do the exercise for exactly five minutes in the middle of every practice.

DELA: Well, over the last three seasons, your team’s batting average has been ten percent higher than the rest of the league. Your system must work.

SARAH: Whoa! Wait a minute. What if the thing that causes your kids to hit better is the fact that you practice more often, or that you’re better at picking players, or that you give them more confidence in another way? I’m not convinced.

DELA: Okay, so there’s some relationship between Patricia’s visualization exercises and increased batting averages, but the visualization exercises might not be the cause.

PATRICIA: I have an idea. Next year, let’s take the list of every kid in the league and randomly pick 60 for the visualization exercise, and 60 to track without giving them the visualization exercise. Then we’ll compare the batting averages of the two groups.

DELA: Okay, I’ll go for that, but is this really fair? I mean what about the kids on your team that won’t get the visualization exercise from you this year? Is it fair to them?

PATRICIA: I agree—that’s a tough call, but I’ll be doing the exercises with more kids than I ever have before.

SARAH: I don’t think we’re doing anything wrong to the kids and I’d like to see the results.

DELA: How can we be sure we aren’t measuring in a biased way?

SARAH: The umpires will be calling the players safe or out, and the umpires won’t know about our experiment. And we shouldn’t tell the kids what we’re doing either.

PATRICIA: This is going to be great.

One year later…

DELA: The 60 kids in the visualization group had batting averages seven percent higher than the 60 we selected to track but not give the visualization exercise.

PATRICIA: I’m pretty convinced that the visualization exercise works, but I supposed we’d have to do it a bunch more times in other towns to be sure.

SARAH: You’re right, but at this point, I’m ready to say it looks like I was wrong. I think your karma ran over my dogma.

PATRICIA: No sweat. This was a good thing to do. I wish other people were as willing as you are to actually think carefully and test out their hypothesis. Another pitcher? Or would you like a double or a triple? Maybe a slider?

  1. Quote or paraphrase the part of the conversation that illustrates dogmatic rather than empirical thinking.
  2. Quote or paraphrase the part of the conversation that illustrates the theory and/or the hypothesis?
  3. Quote or paraphrase the part of the conversation that illustrates the correlation.
  4. Quote or paraphrase the part of the conversation that illustrates the possible third variables.
  5. Let’s say that you were able to access all the patient data from a major urban hospital.  You found that 18% of all patients smoke cigarettes, but that 57% of schizophrenics smoke cigarettes.  Because the people being studied decided themselves whether or not to smoke (rather than the researchers randomly assigning smoking), the relationship between the two variables (schizophrenia and smoking) is called a(n) ___________.
  6. Let’s say you wanted to do further research on the relationship between schizophrenia and smoking.  Explain, in two or three short sentences, how you would do an experiment attempting to prove that smoking CAUSES schizophrenia.  (Hint: You couldn’t really do this experiment financially or ethically, so it will seem ridiculous.)