What are the elements that could have raised reasonable doubts about the accuracy of a police identification?

"there were elements that could have raised reasonable doubts as to the accuracy of the identification. These elements included the suddenness and unexpectedness of the event, discontinuity and other difficulty of observation, fear and other stress at the time of perception, overestimation of the duration of the event, 'feedback' factors following the event, failure or uncertainty of several witnesses in selecting defendant's photograph from police displays, and, particularly important, apparent cross-racial identification discrepancies." (People v. McDonald, supra, 37 Cal.3d 351, 375-376, 208 Cal.Rptr. 236, 690 P.2d 709.)