Family-owned companies run by outsiders appear to be better managed than other companies, a study finds, while family-owned companies run by eldest sons tend to be managed relatively poorly. Moreover, the prevalence of family-owned companies run by eldest sons in France and the United Kingdom appears to account for a sizable portion of the gap in the effectiveness of management—and perhaps in performance—that we observe in their companies relative to those of Germany and the United States.

These findings come from a study of more than 700 midsize manufacturers in France, Germany, the United Kingdom, and the United States. The study, conducted by McKinsey and researchers at the London School of Economics,¹ looked at the quality of key management practices relative to performance metrics (such as total factor productivity, market share, sales growth, and market valuation) and found that they are strongly correlated.² On a scale of one to five, with five being the highest, US and German manufacturers scored best on these metrics (3.37 and 3.32, respectively), while French and UK companies scored worst (3.17 and 3.09).³

The average management score for...