How much similarity between an uncharged act and a charged crime?

The degree of similarity required between the uncharged act and the charged offense varies, depending on what the uncharged act is used to prove. Here, the prosecution offered the bad acts to prove knowledge and absence of mistake. This use requires the least degree of similarity because, as in the case in which intent is the fact to be proved, the evidence of the uncharged crime is admissible to prove the state of mind accompanying the act; that defendant committed the act itself is conceded or assumed.¹⁵ (See generally People v. Foster (2010) 50 Cal.4th 1301, 1328.)