An investigator conducts a case/control study to examine whether self-reported residential organochloride pesticide exposure increases breast cancer risk in women residing in New York City, New York. Women with breast cancer, the cases, were recruited from a pool of patients seeking care at one hospital in New York City that is world renowned for its breast cancer care. In fact, women come from all over the US to seek breast cancer care at this hospital. Controls were recruited from women who were obtaining care in the emergency room at the same hospital, and were typically women who lived in the neighborhood surrounding the hospital. What type of bias could this method of case and control identification and enrollment introduce?

Selection bias - controls will not represent the exposure probability of the population that gave rise to the cases since cases come from all across the U.S. whereas controls come from the area surrounding the hospital.

Information bias - controls were more likely to participate in the study than cases.

Information bias - cases were recruited from a registry and controls from a population sample.

Selection bias - while cases represent the exposure probability of a known underlying source population from the neighborhood around the hospital, controls represent the source population of all of NYC.