In the fields of medicine, biotechnology, and pharmacology, drug discovery is the process by which new candidate medications are discovered. In 2016, the total global drug discovery market was valued at around 35.2 billion U.S. dollars. It is estimated that the market will grow to some 71 billion dollars by 2025. Modern drug discovery involves the identification of screening hits, medicinal chemistry, and optimization of those hits to increase the affinity, selectivity (to reduce the potential of side effects), efficacy/potency, metabolic stability (to increase the half-life), and oral bioavailability. Once a compound that fulfills all of these requirements has been identified, it will begin the process of drug development prior to clinical trials. One or more of these steps may, but not necessarily, involve computer-aided drug design. Modern drug discovery is thus usually a capital-intensive process that involves large investments by pharmaceutical industry corporations as well as national governments.