Two studies in JAMA Pediatrics offer U.S. parents evidence to back their attempts at limiting sedentary screen time in their homes.
The first study reports that adding a physically active videogaming component to a weight management program increases physical activity significantly (if modestly). In a 16-week trial, researchers provided overweight children with active gaming devices in addition to the weight loss program given to the controls. The gamers had an average increase in moderate-to-vigorous activity of about 8 minutes per day relative to controls. That translates to about 4 pounds of fat over the course of a year.
The other study simply asked whether children between ages 10 and 14 had televisions in their bedrooms. The researchers then measured BMI 2 and 4 years later. Having a TV (60% did) was associated with an excess BMI of almost 0.6 at year 2 and almost 0.8 at year 4 relative to not having one.
a) Which study is the experimental one? What are the IV's and DV's in the experiment? Sketch a graph of the results, as described in the short summary.
(Follow the link to visit the full article and view the results of the study.)
b) Which study is the correlational one? What are the two main variables in the study, according to the summary?
(If you visit the full article, you can see what variables the researchers controlled for in the study.)
c) Can the first study support the causal claim that "giving overweight kids and active gaming device can cause them to lose body fat"? Apply the three causal criteria to analyze whether the study can support this claim.
d) Can the second study support the causal claim that "having a TV in the bedroom causes kids to gain weight?" Apply the three causal criteria to analyze whether the study can support this claim.
*Thanks to my colleague Gordon Bear for sharing these abstracts with me!