Dr. Jones is conducting some research on two college campuses involving food allergies. At one campus educational information on the diagnosis of food allergies is disseminated (Campus A) while it is not distributed at the other campus (Campus B)

Dr. Jones measures through random email surveys, students' knowledge of food allergies. During the week she is disseminating the information at Campus A the student newspaper also runs a story about students with food allergies which is not part of Dr. Jones' program. If the student newspaper article influences students' knowledge of food allergies, what potential confounding variable is at work in this example?


a. history
b. maturation
c. differential history
d. differential attrition

C