A client has just come to your clinic and asked about a new…

A client has just come to your clinic and asked about a new treatment for her cat with diabetes. You have never heard to the treatment she’s inquiring about, so you excuse yourself from the room to go do a quick literature search.  There is not much literature on the new treatment, but there you find three papers:  a case report, a cross sectional study, and a randomized controlled trial.  You want the most credible study you can find, so you opt for the:

You are in the process of describing a novel disease in cats…

You are in the process of describing a novel disease in cats, and want to estimate how long cats with this disease live, so that pet owners can be prepared. To estimate longevity, you recruit cats with this diagnosis from several veterinary clinics. Each cat must have at least one follow-up visit to monitor disease progression 3-4 weeks after initial diagnosis. Unbeknownst to you, 30% of cats with this disease die within a week of diagnosis. What type of bias did your enrollment criteria cause?

12 hours after a class picnic you both attended, you and you…

12 hours after a class picnic you both attended, you and your buddy come down with the stomach flu. Deciding that the potato salad must have been the culprit, you both swear off the stuff forevermore. You read in the news a couple days later that Rico’s Oyster Hut was the source of an outbreak of norovirus in town. The dates they served contaminated food match up perfectly with your visit to Rico’s for brunch before the class picnic. Somehow, you both forgot you ate there! What bias is this an example of?