Read the following abstract and explain what it shows. A rate ratio of 1 means there is no difference in rates, and a confidence interval for rate ratios that captures 1 means there is no significant difference in rates. (An intensivist is a doctor who specializes in intensive care.) We conducted a 1-year randomized trial in an academic medical ICU of the effects of nighttime staffing with in-hospital intensivists (intervention) as compared with nighttime coverage by daytime intensivists who were available for consultation by telephone (control). We randomly assigned blocks of 7 consecutive nights to the intervention or the control strategy. The primary outcome was patients' length of stay in the ICU. Secondary outcomes were patients' length of stay in the hospital, ICU and in-hospital mortality, discharge disposition, and rates of readmission to the ICU.