One study used the method of observing children on the playground to watch how they played together to identify children who displayed aggressive behavior. After analysis, the researchers found that the children who were spanked showed more aggressive behavior than those who were not spanked. Studies like this usually make no investigation into the exact techniques used to discipline children. As a result, parents who become exasperated, lose their tempers and strike their children in anger, and parents who use principled discipline are lumped into the same category, even though the results of their discipline as measured in the children's behavior may be markedly different. This is known as starting with a supposition and then gathering data to prove it.
Christians also start with a supposition and attempt to prove it.
If this research was done in a neighborhood that was devastated by the epidemic of fatherlessness common in the inner city, it would most likely include a disproportionate number of dysfunctional families. In that case, poor parenting may in itself be the cause of observed aggressive behavior, which does not prove that spanking was the cause. These problem children might act the way they did because of improperly administered discipline and poor parenting techniques. The prevalence of broken homes and the lack of fathers is statistically linked with aggressive behavior and crime among youth. Studies such as the one above are hailed as scientific proof, but the truth is they are often biased through faulty design or inadequate research.