As for the rest, studies show a wide spectrum running from family firms, many of them poorly managed, to well-run high-performers, some of them kept to the mark by private-equity funds.

其余的，多份研究表明，则各有千秋，从家族公司(许多管理差劲)到运行良好的表现出众者(其中有些由私募基金进行监管)。