In a recent article, fagerberg [struct. Change econ. Dyn. 11 (2000) 393] finds changes in the employment share of the electrical machinery industry to positively impact the manufacturing sector productivity growth. Fagerberg's approach has some methodological drawbacks, however. This note seeks to complement fagerberg's analysis by estimating the impact of the employment share of technologically progressive industries using a more adequate methodology. Fagerberg's claim that the share of the ‘electronics’ industry positively affects manufacturing is confirmed. However, the size of the impact, and as a consequence the extent of spill-overs, is found to be much smaller than estimated by fagerberg.