 Some researchers have suggested that the increase on crime statistics could be partly explained by the stricter approach to schoolyard fights and bullying, leading to a criminalization of behaviors now defined as "assault" behaviors (while they were simply negatively perceived before).The increase in the proportion of female violent crime would thus be explained more by a change in law enforcement policies than by effective behavior of the population itself.According to the report aforementioned, "Evidence suggests that aggressive and violent behavior in children is linked to family and social factors, such as social and financial deprivation; harsh and inconsistent parenting; parents' marital problems; family violence, whether between parents, by parents toward children or between siblings; poor parental mental health; physical and sexual abuse; and alcoholism, drug dependency or other substance misuse by parents or other family members."