Design of Clinical Radiologic Research

The components of clinical research design--the research question, the review of prior research, the study design, the study subjects, the study measurements, the statistical analysis, and the critical analysis--have been discussed. These components relate to the overall philosophy of the research process in the following manner. The driving force behind research is the desire to understand a universal truth (Fig. 6). The research question is formed to reflect the truth sought. Next defined is the specific target population and the phenomena of interest with regard to the sought-after truth. The study is then designed with a study plan detailing timing and location and an intended sample population chosen to reflect the target population. The phenomena of interest are translated into measurable intended variables. Care is needed to identify the systematic error that can be introduced at this stage; outside opinion can be invaluable. The actual study results from the implementation of the study design. The actual subjects may differ from the intended sample population due to a low recruitment rate or a large dropout rate. The actual measurements may differ from the intended variables due to unsuspected confounding variables or random errors. Statistical analysis is performed on the study findings to infer truth within the study. This truth may be affected by random and systematic errors in implementing the study. Truth in the study is then inferred to reflect truth in the universe. Systematic and random errors in study design may affect the validity of that deduction, but that deduction is the only way we have of understanding universal truth.