Health care workers are at risk of being exposed to blood-borne pathogens through needle-stick and other sharp object injuries. The pathogens of primary concern are the human immunodeficiency virus, hepatitis B virus, and hepatitis C virus. When a needle-stick injury occurs, workers report the incident to their supervisor. This information is forwarded to county health departments and ultimately to the Centers for Disease Control and Prevention (CDC). A CDC researcher used these data to compare needle-stick injuries in community hospitals and tertiary-care hospitals. Is this a paired or independent comparison? Explain your answer.
Are the stick-injury victims paired up?
To determine whether this is a paired or independent comparison, we need to understand the difference between these two types of comparisons.
In a paired comparison, the measurements or observations are made on two related or paired subjects. These subjects are matched or linked together in some way, and each subject contributes two data points for comparison. For example, if we were comparing the effectiveness of a particular treatment in two groups of patients, a paired comparison would involve measuring the outcomes in each patient before and after the treatment.
On the other hand, an independent comparison involves comparing two distinct groups of subjects, with no link or pairing between them. Each subject contributes only one data point to the comparison. For instance, comparing the effectiveness of a treatment between a group of patients receiving the treatment and another group receiving a placebo would be an independent comparison.
In the given scenario, the researcher compares needle-stick injuries in community hospitals and tertiary-care hospitals. Since the injuries are reported individually by the workers to their supervisors and then forwarded to public health authorities, there is no pairing or connection between the reported injuries from different hospitals. Therefore, this is an independent comparison. The researcher is comparing the rates or frequencies of injuries in two distinct groups (community hospitals and tertiary-care hospitals) without any direct link or pairing between individual injuries.
To confirm this categorization and further understand the study design, it may be necessary to review the specific methods and data analysis techniques employed by the CDC researcher.