I have been advised by Tusla that, where allegations of abuse are made, by their nature the allegations must be assessed on an individual basis. Allegations are assessed in the context of whatever information is known about the child or the person suspected of alleged abuse. A previous unfounded allegation is considered by Tusla to be significant, and should be judged in the context in which it was unfounded.
One possible reason for an outcome of unfounded is that the complainant would not engage in the process and make a complaint. This would present a different context to one where the allegations were judged, on the balance of probabilities, to be unfounded.