What type of study was the Bruckner study?

• A. Retrospective study at a single center
• B. Prospective randomized trial
• C. Case series
• D. Cross-sectional survey

Answer: (A)

A retrospective study means the researchers looked back at data that already existed rather than collecting new information going forward. When it’s described as a single-center study, all the data come from one institution rather than multiple sites. The Bruckner study fits that pattern: it analyzes past records from one hospital to assess outcomes, without planning new data collection or random assignment.

A prospective randomized trial would involve enrolling patients forward in time and randomly assigning them to different treatments, with data collected as the study progresses—that isn’t how this study was conducted. A case series describes a set of patients treated in a similar way, usually without a comparison group or predefined hypothesis. A cross-sectional survey measures a snapshot in time, typically to estimate prevalence, not to look back at past records or follow outcomes over time.