<P> A patent is an exclusionary right--preventing others from entering the market--and so its effect may be to increase the patent proprietor's income from that market . The major economic effect is the exclusivity period of the patent rights, when exploitation pays back for the enterprise that funded research and development . However, patenting alone does not guarantee for marketing success . </P> <P> The right to exclude others from entering market with copies is, however, potentially extremely valuable as it can mean total exclusivity in that market for the duration of the patent (generally 20 years from filing). For example, worldwide sales of a patented pharmaceutical can be millions of dollars per day, whereas the generic equivalent would later sell for less than half the price . </P> <P> Income improvement from a patent is difficult to measure . One may attempt to measure the difference in price between an "improved" product and its "unimproved" counterpart, or compare the price of the product with that in markets where (or when) it has not been patented . More directly measurable income is that which is received from the licensing or sale of patent rights, or from successful litigation of infringement . </P> <P> Under traditional patent doctrine, innovation is spurred by patent law in at least two ways . (1) The inventor can secure exclusive rights, and therefore working on innovation gives the inventor a higher probability of financial rewards in the market place . (2) Publishing the invention, rather than keeping it a trade secret allows others to build upon the technology . Both of these have been challenged based upon economic analysis . The "rewards" theory has been criticized as ignoring the risky prospective nature of the "reward", and the post patent costs of cost - engineering and marketing . The "publication of the patent as spurring innovation" branch has been criticized indicating that it produces patent thickets and encouraging others to design around existing technology rather than to build upon it . </P>

Who has the power to provide patents why is this significant to the economy