When can an affidavit containing information obtained from an informant be relied upon to establish probable cause?

When the information in the affidavit is obtained from an informant, that person's veracity, reliability, and basis of knowledge are not absolute requirements. Rather, they are relevant factors, which may "illuminate the commonsense, practical question whether there is `probable cause.' " (Illinois v. Gates, supra, 462 U.S. at p. 230; People v. Terrones (1989) 212 Cal.App.3d 139, 146.) A deficiency in one of these factors may be compensated for by a showing of other indicia of reliability. (Illinois v. Gates, supra, at p. 233).