Clinical Studies


We use clinical studies and trials to provide information which helps us to understand how patients become unwell, and how best to prevent and treat this when it happens.

These studies always involve patients but can be very different in the way they are designed. Observational studies involve watching what happens to patients and gathering information about them, whilst interventional studies usually test some form of treatment to see how patients respond. The latter are more commonly described as clinical trials.

Clinical studies vary widely in size from fewer than ten to hundreds of thousands of patients. It is usually better to include as many people as possible so that the findings better represent all patients. However, this may be difficult when researchers study rare diseases or need to make complex measurements.

At the NIAA Health Services Research Centre, we are mainly focussed on running clinical studies of large numbers of patients using very simple methods. This approach helps us to understand how things work in the normal day to day life of the National Health Service. We support and lead observational studies of patient outcomes after surgery, and clinical trials of simple treatments that help to ensure more patients make the best possible recovery after their operation. Because surgery is such a widely used treatment, we believe that even small improvements in how we work can benefit the lives of many thousands of people each year.

Primary Research

Primary research involves the collection of original data. Primary research may be quantitative or qualitative:

  • Quantitative research (in the context of HSR) includes clinical trials, cohort studies, questionnaires and surveys.
  • Qualitative research (in the context of HSR) involves includes interviews, focus groups, participant observations and ethnographies.

The design of Primary Research can (and usually should) be informed by secondary research.

Secondary Research

Secondary research involves the summary, collation and/or synthesis of data which has already been collected.

The principal methodology in medical secondary research is the systematic review. The aim of the systematic review is to avoid the bias inherent in a narrative (or subjective) review process by establishing a priori criteria for study selection, data extraction and analysis. Quantitative analysis within systematic reviews commonly uses meta-analytic statistical techniques.