 While much research has been done to correlate race, income level and crime "frequency", typically of less serious criminal behavior such as theft or larceny, research has shown there to be no significant correlation between race, income level and crime "seriousness".Thus, conflict theory encounters difficulties in attempting to account for the high levels of violent crime such as murder, homicide and rape, in minority populations.Strain theory, which is largely derived from the work of Robert K. Merton in the 1930s and 1940s, argues that social structures within society which lead to inequality and deprivation in segments of its population indirectly encourage those segments to commit crime.