Question

Suppose a hospital observes 210 CLABSI events when the expected baseline rate is 180 events. In that case, the SIR = 210/180 = 1.17. Does the observation that the hospital’s SIR > 1 permit one to conclude that the hospital’s CLABSI rate is, in fact, greater than the expected baseline rate?

Yes, by definition, SIR  = 1.17 indicates that the actual rate is greater than the expected rate.

Yes, there are 30/180 = 16.7% more CLABSI cases than should be expected by chance.

No, the SIR statistic is not an efficient estimator of the population SIR parameter.

No, sampling variation implies that the observed rate will not be exactly 180, even if 180 is the true rate.

Answer 1

Suppose a hospital observes 210 CLABSI events when the expected baseline rate is 180 events. In that case, the SIR = 210/180 = 1.17. Does the observation that the hospital’s SIR > 1 permit one to conclude that the hospital’s CLABSI rate is, in fact, greater than the expected baseline rate?

No, the SIR statistic is not an efficient estimator of the population SIR parameter.

Factors that increase the risk of central line-associated bloodstream infections (CLABSIs) are not fully understood. Using national datasets, we found that inpatients' hospital experiences were significantly associated with an increased risk of ICU reported CLABSIs.