Industry diversity, competition and firm relatedness: the impact on employment before and after the 2008 global financial crisis. Regional Studies. This study investigates the extent to which indicators of external-scale economies impacted employment growth in Canada over the period 2004–11. It focuses on knowledge spillovers between firms while accounting for Marshallian specialization, Jacobs’ diversity and competition by industry, as well as related and unrelated firm varieties in terms of employment and sales. It is found that the employment growth effects of local competition and diversity are positive, while the effect of Marshallian specialization is negative. Diversification is found to be particularly important for employment growth during the global financial crisis and immediately thereafter.