Researchers have found that the more World Cup soccer a student watches the better they do on their exams. Students reported the amount of World Cup soccer they had watched in the two weeks leading up to their midterm exams. The more soccer watched, the better the student’s exam grades tended to be. Researchers are not yet sure why soccer viewing improves intelligence, but plan further research during the next World Cup qualifiers as well as research examining other sports. Which of the following BEST captures the most significant flaw in this research as it is written? What type of design is this? Using an exam score as a measure of intelligence is an example of?