True but there are several factors that improve our confidence with data today. Now researchers need to register trials, increasing publications that show undesirable results. We have a larger volume of studies, strengthening the conculsions drawn from cohort studies. We also have more studies without glaring conflicts of interest. That's not to say issues are eradicated from research. Bias and conflicts of interest remain in many studies. But there are several topics, such as the negative impact of smoking on health, that we have certainty on.