This type of study design, known as "case-control," cannot prove cause-and-effect.
这种类型的研究被称为病例对照研究，它不能够证明两者之间的因果关系。
2
Those types of studies have been coming out in the last 10-15 years and have not supported the original findings [from case-control groups].
这一类型的研究持续了10到15年，结果表明，通过病例对照研究而得出的结论站不住脚。
3
Many researchers fault case-control work as being a weak method for showing direct causality, especially because it is subject to substantial recall bias.