What is the impact of admitting evidence that involves crimes other than those for which a defendant is being tried?

It is well settled that "admission of any evidence that involves crimes other than those for which a defendant is being tried has a 'highly inflammatory and prejudicial effect' on the trier of fact." (People v. Thompson (1980) 27 Cal.3d 303, 314, 165 Cal.Rptr. 289, 611 P.2d 883, fn. omitted.) Such evidence must be scrutinized carefully. Its admission depends on: 1) the materiality of fact sought to be proved or disproved, 2) the tendency of the uncharged crime to prove or disprove the material fact, and 3) the existence of any rule or policy requiring the exclusion of relevant evidence. (Id. at p. 315, 165 Cal.Rptr. 289, 611 P.2d 883.) In order to satisfy the materiality requirement, the fact proved or the permissible inference to be drawn must result in or logically lead to the establishment of an ultimate fact in dispute. (Id. at p. 315 and fn. 14, 165 Cal.Rptr. 289, 611 P.2d 883.)