Scientific and Clinical Research

A professional interest in research questions, design and findings.

Scientific and clinical research is the effort to measure systematically what an intervention does in people. Whether that measurement can be trusted rests not on statistics alone but on the fit between design and question, on the ethical framework, and on the study having been registered in advance.

Matching design to question

Not every question is answered by the same design:

• Randomised controlled trial — gives the strongest answer to a question of causation.
• Cohort study — follows outcomes over time where randomisation is not possible.
• Case-control study — looks backwards from the outcome, useful for rare events.
• Cross-sectional study — measures frequency at a point in time and cannot establish causation.

In observational designs confounding is the central problem: an unmeasured variable may be the real reason behind an apparent association. Statistical adjustment reduces that risk without removing it.

The ethical framework

The founding principles of research in humans are set out in the Declaration of Helsinki: the wellbeing of the participant takes precedence over scientific and societal interests, informed consent must be genuinely obtained, and an independent ethics committee must review the study. Informed consent is a process rather than a signature.

Registration and sample size

Registration before enrolment begins makes any later change to the primary endpoint or analysis plan traceable. A sample size calculation determines in advance how large a difference a study can detect; where a study is underpowered, the absence of a significant result does not show that there is no effect.

Safety data

How adverse events are defined, the severity scale used to grade them and how their relationship to the intervention is judged should all be specified in advance. Rare adverse effects usually cannot be detected at pre-authorisation sample sizes, which is why post-authorisation surveillance is a separate stage.