The table reveals that no previous study has used productivity growth or growth in value added as growth indicators to define HGFs when their economic contribution has been analyzed. 6 Productivity has been discussed in the literature on HGFs prior to this paper (Acs et al., 2008; Fritsch and Mueller, 2004; Littunen and Thomo, 2003). However, little has been made of this observation. Fritsch and Mueller (2004) stress the difficulties in gathering data on productivity, which can explain why no previous study has explicitly addressed this issue. Furthermore, while most studies discuss the contribution of HGFs to employment, no study.
