control for sth.困难

To find out, the researchers controlled for various [factors] that might make firms more likely to invest — like size, industry, and sales — and for indicators that a place was [desirable] to live in, like growth in wages or population.

为了弄清楚这一点，研究人员控制了可能使公司更倾向于投资的各种{{10}}——如规模、行业和销售额——以及表明一个地方{{11}}居住的指标，如工资或人口的增长。