Variation and selection patterns

In document Technological trajectories and environmental policy: the transformation of the automobile (Page 80-84)

3.5 Empirical results

3.5.1 Variation and selection patterns

In order to derive insights into knowledge dynamics, we ex-plore the patterns of variation and selection within the elec-tric and hybrid technological space. As stated above, these technologies have faced growing concern, at least from a reg-ulatory perspective, in two main periods, during the '70s and from the '90s onwards. This increasing interest has encour-aged technological communities to develop potential solutions to the technological weaknesses that these technologies have experienced. Figure 3.3 emphasises this feature through the number of variations that are proposed to the selection envi-ronment by technological developers. In this case, we consider variations as the dierent combinations of 8-digit IPC codes that are disclosed each year. It should be noted that this count, as well as the others reported in Figure 3.3 and Fig-ure 3.4, does not refer to how many patents with a specic

IPC code combination are led each year, but on the contrary, it equally weights each combination. This allows us to concen-trate this part of the analysis on the underlying dynamics of technological knowledge variation instead of focusing on how much a specic combination has been recognised as a promis-ing technological domain to further develop, an issue that will be examined in the rest of the chapter. However, in order to obtain clearer, more reliable results, we include only those combinations of IPC codes that have been assigned to at least two patents over the period 1900-2011 in the analysis.

Figure 3.3: Variation pattern in electric and hybrid vehicles

Source: Own elaboration

After small and steady changes that characterised the evo-lution of EV and HV from the beginning of the 20th century to

Figure 3.4: Trends in selection in electric and hybrid vehicles

Source: Own elaboration

the 1970s6, the number of variations slightly increased at the beginning of the '70s (Figure 3.3). This trend is then followed by a decline during the '80s and experiences a sharp rise after 1990. With regard to this point, we highlight the eectiveness of the ZEV mandate in triggering technological development related to these technologies, as can be seen from the increase in the number of variations during 1990-1999. However, a few years later when the mandate was relaxed in 1996, abolishing the 1998-2002 requirements and leaving in place 10% by 2003, the count undergoes a rapid decrease in 1999, regaining its momentum from 2002 onwards. This second rise in variations is associated with a period of discontinuity that occurred with the introduction of HVs onto the market. From 1997-1998, the year when the Toyota Prius I was launched, many inventors

6For the sake of comprehension, these values are not reported in Figure3.3

began to improve HVs technologies as reported in Figure 3.1.

Nevertheless, even if the number of variations increased almost steadily from 1990 onwards, the introduction of new variations that have been never scrutinized before, followed a dierent trend, i.e. sharply growing from 1990 to 1992, slightly increasing from 1995 to 1999 (when it reaches the maximum) and gradually decreasing from then on. This rep-resents an insight into how the exploration of new technologi-cal solutions increased as a consequence of the changing envi-ronment in which EVs and HVs evolved, and decreased with time. In addition, the dierence in the number of variations and new variation trends underlines the fact that technological advances are increasingly directed towards specic technolog-ical domains, that is, the technologtechnolog-ical space, as well as the underlying knowledge structure related to electric and hybrid vehicles, are shaped and begin to characterise further develop-ments.

Nonetheless, to obtain a clearer view of the patterns that distinguish knowledge dynamics, we derive another insight that shows whether the evolving knowledge structure exploits the variations proposed in previous years. In the analogy with biological evolution, we assumed that selection occurs when patents cite previous knowledge, building on the fact that when previous patents are cited their technological knowledge rep-resents a knowledge source for citing ones. Using citations we face an additional problem related to the time lag between cited and citing patents. In this regard, Figure 3.4 accom-plishes the task showing both the number of variations that are selected by forward variations (Selection (Citied)) and the number of variations that select previously introduced ones (Selection (Citing)). Focusing on the citing variations, we can observe that after the introduction of the ZEV mandate, the number of variations that select (cite) previous ones gradually rises until 1999 and faces sharp growth from 2000-2007.

Dur-ing the same period, the creation of new variations (Figure3.3) gradually declines, meaning that whereas the creation of new IPC combinations decreases, the selection of previous combi-nations increases. We interpret these results as evidence that the exploitation of previous variations is increasing. This is conrmed by the trend in the number of variations cited that goes up with some uctuations from 1990 onwards.

Finally, Figure 3.4 shows that the average dierence be-tween citing and cited years uctuates from the beginning of the '70s to the end of the '90s and levels o from 2000. It is interesting to observe that whereas during the '90s this average

utters from 6.2 to 13.7 years, at the beginning of the 2000s, it stabilised at around 5.4. This provides another insight that, while in the former period variations recombined knowledge bits from older variations, in the latter they selected more re-cent knowledge from this explorative phase.

In conclusion, we should point out that the values reported in the last 3-4 years in Figure 3.3 and Figure 3.4 should not be considered. The decreasing trends are mainly due to the time needed to develop new variations, exploit the more recent ones, and le and publish patent applications.

3.5.2 Understanding what has been selectively

In document Technological trajectories and environmental policy: the transformation of the automobile (Page 80-84)

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