-R&D employment. The third essay focuses on the productivity effects of R&D. The results of empirical analyses are two-fold. In the … short run (in 1-2 years), no statistically significant productivity impact of R&D is found. However, R&D does have an … of almost 5 years is needed to capture the productivity impact of R&D. The fourth essay studies how patent quality …

second essay presents empirical evidence on the productivity impacts of stock option schemes. It shows that when endogeneity … firm productivity. The finding is consistent with the hypotheses that predict negligible effects of option plans on firm … performance. The third essay studies whether, instead of productivity, option schemes affect firm technical inefficiency. The …