Question

An article titled "Guard Your Kids Against Allergies: Get Them a Pet" (San Luis Obispo Tribune, August 28,2002\()\) described a study that led researchers to conclude that "babies raised with two or more animals are about half as likely to have allergies by the time they turned six." Explain why it is not reasonable to conclude that being raised with two or more animals is the cause of the observed lower allergy rate.

Short answer

Simply put, it's important to distinguish between correlation and causation. Observationally, while the presence of pets and lower allergy rates could be correlated, declaring pets as the root cause requires concrete evidence usually obtained via the scientific method. Plus, there could be multiple other influencing factors at play - making it imprudent to attribute the decrease in allergies solely to the presence of pets.

Step-by-step solution

Understanding Correlation vs Causation

There is a very important distinction to understand when interpreting studies like this. Correlation merely implies a relationship or pattern observed between two variables, in this case, the presence of pets and the prevalence of allergies in children. However, a correlation does not automatically imply causation. To establish causation, it must be proven that one variable directly affects the other, that is, that having pets directly results in fewer allergies.

Consideration of Confounding Variables

In this kind of study, there could be numerous other factors interacting and contributing to the lower allergy rates among children who live with two or more pets. These are called confounding variables. For instance, maybe these kids often play outside (due to walking their pets) and this exposes them to outdoor allergens that boost their immune system. Also, the type of household environment that simultaneously supports having many pets may also play a role in preventing allergies.

Importance of Scientific Method for Causation

To say 'being raised with two or more animals is the cause of the observed lower allergy rate' is a strong statement that requires strong evidence. This is usually obtained through the scientific method. Ideally, to test this hypothesis, you would need a random and representative sample of children, then randomly assign some to be raised with two or more pets and some to be raised without pets, controlling as many other variables as possible. Then, if there was a significant difference in allergy rates, you could conclude that pets cause lower allergy rates. However, ethical and logistical considerations make this study difficult to carry out. Without such a study, it's not reasonable to conclude that pets cause fewer allergies based on observational findings alone.