This study examines how community-based mandated reporters understand and interpret "reasonable suspicion", the standard threshold for mandated reporting of suspected child abuse. Respondents were asked to identify the probability necessary for "suspicion of child abuse" to constitute "reasonable suspicion". Data were analyzed for internal consistency, evidence of a group standard, and associations with professional and educational demographics. There was a 90.4% response rate (1,233/1,364). On both ordinal probability and estimated probability scales, respondents demonstrated wide variability in the thresholds they identified for what constitutes "reasonable suspicion". Comparing individual responses for the two scales, 83% were inconsistent. Responses on the estimated probability scale were correlated with frequency of reporting child abuse, professional background, and prior education on child abuse. Lack of consensus in how community professionals interpret "reasonable suspicion" raises the question of whether more specific training is needed for this threshold to be understood, interpreted, and applied in a consistent manner. (Contains 4 figures and 2 tables.)