6. Discussion and conclusions
As mentioned at the beginning of the paper, our aim was to introduce the ‘functions of innovation systems’ as drivers within the roadmapping process (i.e. as layers of the roadmap). The rationale behind the use of the ‘functions approach’ lies in i) the notion of functions as ‘drivers’ of innovation systems, as pointed out by previous literature; and ii) in the notion of sectoral roadmaps as being visual representations of how a sector evolves – or should evolve – over time, with a main focus on the generation and diffusion of technologies and innovations (i.e. sectoral roadmaps depict essentially technological innovation systems). Furthermore, the need for a ‘systems perspective’ has been recently discussed within the roadmapping literature (see for example, Ahlqvist et al. (2012) and Saritas and Oner (2004)) leading to the need for contributions in this stream of research.