According to John F. Duffy, in "Inventing Invention: A Case Study of Legal Innovation," the chart below summarizes some of different standards for patentable invention that have been employed in the last half millennium:
Obviousness doctrine will be least important in societies where (1) patent rights are expensive to obtain and to enforce, (2) the pace of social change is relatively slow, (3) few inventors are likely to working on similar projects, and (4) patent rights are kept relatively narrow. These conditions prevailed prior to the 19th century, and during that period, a clear conception of obviousness did not exist. As patents became easier to obtain and broader, inventors more numerous, and society less static, the need for obviousness or some similar doctrine grew more dire. Still, the progress toward a worldwide obviousness standard was not linear. . . .
Subjective tests look to the inventor’s own efforts. Such tests have been employed only occasionally throughout history. In the United States, a subjective approach to judging patentability is now precluded by the last sentence of § 103(a). The tests in the right column are objective; they are not contingent on any efforts or qualities of the inventor. Roughly, the tests listed lower in the columns are more difficult to satisfy.
In other parts of the world, the Japanese Examination Guidelines require consideration of whether a person skilled in the art could have easily arrived at a claimed invention based on the cited inventions after precisely comprehending the state of the art in the field to which the invention pertains at the time of the filing.
The European Patent Office generally applies the "problem-solution approach" in order to decide whether an invention involves such an "inventive step," by
- identifying the closest prior art, i.e. the most relevant prior art;
- determining the objective technical problem, i.e. determining, in the view of the closest prior art, the technical problem which the claimed invention addresses and successfully solves; and
- examining whether or not the claimed solution to the objective technical problem is obvious for the skilled person in view of the state of the art in general.
- Identifying the inventive concept embodied in the patent;
- Imputing to a normally skilled but unimaginative addressee what was common general knowledge in the art at the priority date;
- Identifying the differences if any between the matter cited and the alleged invention; and
- Deciding whether those differences, viewed without any knowledge of the alleged invention, constituted steps which would have been obvious to the skilled man or whether they required any degree of invention.
The U.S. Supreme Court in Graham et al. v. John Deere Co. of Kansas City et al., 383 U.S. 1 (1966) held that obviousness should be determined by looking at
- the scope and content of the prior art;
- the level of ordinary skill in the prior art;
- the differences between the claimed invention and the prior art; and
- objective evidence of nonobviousness.
In addition, the Court outlined factors that show "objective evidence of nonobviousness". They are:
- commercial success;
- long-felt but unsolved needs; and
- failure of others.
Other U.S. courts have considered additional factors as well. See Environmental Designs, Ltd. v. Union Oil Co. of Cal., 713 F.2d 693, 697-98, 218 USPQ 865, 869 (Fed. Cir. 1983) (considering skepticism or disbelief before the invention as an indicator of nonobviousness); Allen Archery, Inc. v. Browning Mfg. Co., 819 F.2d 1087, 1092, 2 USPQ2d 1490, 1493 (Fed. Cir. 1987) (considering copying, praise, unexpected results, and industry acceptance as indicators of nonobviousness); Diversitech Corp. v. Century Steps, Inc., 850 F.2d 675, 679, 7 USPQ2d 1315, 1319 (Fed. Cir. 1988) (considering copying as an indicator of nonobviousness).
Whether the Federal Circuit has erred in holding that a claimed invention cannot be held "obvious", and thus unpatentable under 35 U.S.C. § l03(a), in the absence of some proven "'teaching, suggestion, or motivation' that would have led a person of ordinary skill in the art to combine the relevant prior art teachings in the manner claimed."An entirely different aproach would be to consider the resulting "Level of Invention," defined by TRIZ author G. S. Altshuller around 1946, as a relative degree of change to the previous system (or solution) as a result of solution of inventive problem (one containing a contradiction).