Positivism is part of the neoclassical period in which crime is studied through scientific technique. Hard determinism is the belief that individuals have no control over crime. Additionally, people were encouraged to make rational choices rather than choosing a life of crime. Lawrence Cohen and Marcus Felson contributed to routine activities theory. Routine activities theory is part of rational choice theory which is part of neoclassical criminology, but it reflects the period of classical criminology. Rational choice theory reflects the period of classical criminology in that this theory believes that criminals make conscious, rational choices. Lawrence Cohen and Marcus Felson said that a person's lifestyle contributes to the amount of space an object will occupy and the type of crime encountered in any society. Routine activities theory states that crime occurs when a motivated offender and a suitable target come together without a competent guardian. A competent guardian is one who does not encourage crime, and the person who has taken steps to prevent crime is less likely to be a victim. The risk of victimization varies depending on the circumstances and the location in which goods and people are placed. Another theory from the neoclassical period is situational choice theory which is part of rational choice theory. This theory views criminal behavior as an activity of choices and decisions formed under situational constraints and favorable timing. Ronald V. Clarke and Derek B. Cornish came together to form the situational choice perspective. The situational choice perspective analyzed the structured choice properties of a probable criminal situation. This is defined as attaching to particular types of crime a constellation of opportunities, costs and benefits. Clarke and Cornish said they indirectly deploy situational strategies to reduce the likelihood of criminal offenses.