An EBP council member is conducting a systematic review on presenting urinary tract infections. Which type of study represents the highest level of evidence?

An EBP council member is conducting a systematic review on presenting urinary tract infections. Which type of study represents the highest level of evidence?

• A. Expert opinion from specialists
• B. Controlled trial without randomization
• C. Well-designed case-control study
• D. Cohort analytical studies

Answer: (B)

The strongest evidence in this set comes from a study that uses a controlled trial design without randomization. Having a control group and a defined intervention observed prospectively allows for a clearer comparison between groups and a more direct assessment of causality than purely observational designs. Even though lack of randomization means there can be confounding factors that aren’t fully balanced, this design still provides a more solid basis for attributing effects to the intervention than studies that simply observe outcomes in groups without a control or with retrospective data. Expert opinion from specialists is considered the lowest level of evidence, as it reflects experience rather than systematic data. Well-designed case-control and cohort analytic studies are observational and susceptible to biases and confounding, which weakens causal inferences compared with controlled trials. Therefore, among these options, the controlled trial without randomization offers the highest level of evidence while examining interventions related to urinary tract infections.

The strongest evidence in this set comes from a study that uses a controlled trial design without randomization. Having a control group and a defined intervention observed prospectively allows for a clearer comparison between groups and a more direct assessment of causality than purely observational designs. Even though lack of randomization means there can be confounding factors that aren’t fully balanced, this design still provides a more solid basis for attributing effects to the intervention than studies that simply observe outcomes in groups without a control or with retrospective data.

Expert opinion from specialists is considered the lowest level of evidence, as it reflects experience rather than systematic data. Well-designed case-control and cohort analytic studies are observational and susceptible to biases and confounding, which weakens causal inferences compared with controlled trials. Therefore, among these options, the controlled trial without randomization offers the highest level of evidence while examining interventions related to urinary tract infections.