April 11, 2018
Child abuse and related fatalities are correlated to age of the child, according to U.S. Department of Health and Human Services data. Younger children are subject to higher rates of abuse and fatalities than older children. The decline in abuse rates as children get older is generally smooth, with no abrupt changes (except for the large drop when the child turns one year old).

Child Abuse by Age 2016
Graph reproduced from Child Maltreatment 2016, p. 19

Child Abuse Fatalities by Age 2016
Graph reproduced from Child Maltreatment 2016, p. 55
The child abuse fatalities data highlights the lack of protection a little differently. There is a clear pattern in fatality rates as they asymptotically head lower towards a rough steady state as children move from preschool age to school age. Again, there is no apparent sign that children are suddenly protected from abuse-related fatalities when they start school.
Could the fact that a large number of young children are already in nursery schools or preschools be the reason we do not see a drop in child abuse rates when they enter school?
No. 93.3% of 5 and 6 year olds are enrolled in kindergartens or elementary schools while only 53.8% of 3 and 4 year olds were enrolled in nursery schools or preschools (see Table 103.10 [https://nces.ed.gov/pubs2018/2018070.pdf]).
If schools in fact protect students from child abuse, we should see a 73 percent increase in the average protection for the older group vs. the younger group. But the data shows no corresponding drop in child abuse rates for the older students.
One would assume that mandated reporting confers some level of protection to students. Further research may uncover factors that offset such protection.
But currently, the best data available indicates mandated child abuse reporting does not turn public schools into “safe harbors” from child abuse and related fatalities. The author knows of no data-based studies that indicate mandated abuse reporting does produce public school safe harbors.