ABSTRACT
This chapter is a list of recipes that tell the general practitioner (GP) the recipes blindly: the GP uses their judgment. It presents three examples, below each of which there are references to the literature. The initial odds in this chapter represent a good starting point for a doctor new to general practice. However, within seconds of assessing a patient—and then over years of acquiring knowledge and experience—the general practitioner’s own initial odds for a particular patient might rightly differ from those cited. Likelihood ratio is a number attached to a symptom, sign or test that tells us whether a particular diagnosis is more or less likely. If one multiplies the initial odds by the likelihood ratio, they get the revised odds. The likelihood ratio is described as positive or negative, depending on whether the symptom, sign, or test is positive or negative.
