Usage patterns
〈事〉の要因となるto become a factor in (something)
The weak yen became a factor in the increase in exports.
要因を分析するto analyze the (contributing) factors
Experts analyzed the factors behind the accident.
要因を探るto search for/investigate the cause
An investigation was conducted to find out the factors behind the decline in performance.
大きな要因a major factor
The declining birth rate is a major factor in the economic stagnation.