According to nardulli's study, how often were motions to suppress evidence filed?

The answer is rarely. Motions to suppress physical evidence are trailed in fewer than 5% of the cases, largely drug and weapons cases though serious motions to suppress identifications and confessions are filed in 2% and 4% of the cases. The success rate of motions to suppress is equally marginal. Successful motions to suppress physical evidence occur in only 0.69% of the cases, while successful motions to suppress identifications or confessions occur much less often. Furthermore, not all who successfully suppressed evidence runaway conviction in which particularly when only an identification or a confession was suppressed. In all, only 46 cases less than 0.6% of the cases studies were nowhere to be found because of the three exclusionary rules combined most of them linking offenses that would have suffered less than six months of imprisonment or first offenders. Finally, the influence of unsuccessful motions on succeeding plea negotiating was found to be marginal if only unsuccessful motions to eliminate confessions caused in any real sentencing concerns.