International comparison proves that duration is a large internal link to patent protection and that it’s measurable.

The first iteration of the GP index quantified the strength of book-law patent protection for 110 countries, in five-year intervals for the period 1960–1990 (Ginarte & Park, 1997). It was subsequently extended by Park (2008) up to the year 2005 and for a total of 122 countries. The index is comprised of five constructs, namely: (i) patent coverage, (ii) membership of international treaties, (iii) enforcement mechanisms, (iv) restrictions on patent rights, and (v) duration of patent protection. The ‘coverage’ construct includes eight variables designed to capture the availability of patent protection in certain industrial sectors where patent protection is perceived as being particularly beneficial to the patent holder, such as the patentability of pharmaceutical products. The ‘membership of international treaties’ construct includes five variables relating to whether or not a country is signatory to patent-related treaties, such as the TRIPS agreement. It should be noted that the TRIPS agreement is concerned not only with matters relating to patents but also with other types of IP such as copyright and trademarks. The ‘enforcement mechanism’ construct captures the existence of laws that can enable patent enforcement, such as the availability of preliminary injunctions. Importantly, in the GP indices this construct concerns only the availability of book-law protection, not how such laws are actually enforced. Nor does it concern other enforcement-related activities. The ‘restrictions on patent rights’ construct considers the existence of laws that have the potential to negatively affectthe appropriation of patent rights by owners, such as those that enable the revocation of patents. Finally, the fifth construct, ‘duration of patent protection’, is measured by one variable where countries offering protection for less than 20 years from the date of application score lower than those meeting or exceeding this condition. The summated value of the binary variables constitutes the total index number for that particular construct. The overall patent protection score of a country reported in the GP indices then consists of the unweighted sum of component construct values, with scores ranging between ‘0’ (which signals an absence of patent protection in a country) and ‘5’ (which signals much higher levels of protection).