The study observed 15,973 defendants in two jurisdictions, making this study the most comprehensive of its kind. Because of the size, the numerical estimates and the causal inferences are more reliable. Specifically, the research design examined defendants whose BAC was just above or below .15 to see if the effect of an increased license suspension by an additional two months has an effect on recidivism.
Without getting into the math which involves multiple variables, the study found that the increased sentences had no real effect of the rate of recidivism. This finding directly contradicts the common theory that defendants will be deterred from committing the same offense if the Court imposes a harsher sentence.