The phrase "to know all factors" means understanding all of the elements or things that contribute to a situation or outcome. It suggests having complete knowledge about the different aspects that affect something. Full definition
There are literally hundreds of known factors in the existing literature, and many papers documenting new factors are published every year. (researchaffiliates.com)
In fact, the centre says they are just two of the whole host of known factors that influence global temperatures - all of which are accounted for by its models. (news.bbc.co.uk)
The international evidence on performance pay is more encouraging, including a recent worldwide look that indicates that students learn more in countries with performance pay plans, all other known factors held constant. (educationnext.org)