Making treatment and prevention decisions for swine should be based on scientific studies, and veterinarian and producer experience. An internet search on a problem will often give a variety of responses, but the value of the information can be low if it is not supported by data. In descending order of reliability, the scientific resources used to make decisions are systemic reviews, randomized blinded clinical trials, observational studies, case reports or studies, peer reviewed manuscripts, and proceedings papers. Producers can run their own clinical trials, but often make the mistake of giving one batch a treatment and using the next batch as control. This can often confound the results due to differences in performance between batches. When making health decisions, producer and veterinarian experience is still invaluable. The combination of a veterinarian’s training and experience with a variety of herds, and the producer’s intensive knowledge of the herd health can help make the best decision for the herd.