the sample for Lombroso's studies were convicted criminals, without a control group, so it's not possible to know whether atavistic characteristics are just as common in the non-criminal population
Goring1913 conducted a study comparing the physical features of 3,000 English criminals with 3,000 non-criminals and found no significant differences in physical characteristics
Lombroso's sample consisted of individuals with psychological disorders and learning difficulties. Perhaps Lombroso confused criminality with psychopathy/ learning disability
the theory that had significant racist undertone. Some of the characteristics identified, such as dark skin, were those typical of African origin