A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
  • Participant

    An individual who is studied in a trial, often, but not necessarily, a patient.
  • Peer review

    A reviewing process for checking the quality and importance of reports of research. An article submitted for publication in a peer-reviewed journal is reviewed by other experts in the area.
  • PHR

    The PHR Programme evaluates interventions taking place outside of the NHS that aim to improve public health.

  • Pilot studies

    This is a definition that has been agreed by the EME, PHR, HTA and RfPB programmes. Pilot studies are a smaller version of the main study used to test whether the components of the main study can all work together. It is focused on the processes of the main study, for example to ensure that recruitment, randomisation, treatment, and follow-up assessments all run smoothly. It resembles the main study in many respects, including an assessment of the primary outcome. In some cases, this will be the first phase of the substantive study and data from the pilot phase may contribute to the final analysis; this can be referred to as an internal pilot. Or, at the end of the pilot study, the data may be analysed and set aside, a so-called external pilot.
  • Placebo

    An inactive substance or procedure administered to a participant, usually to compare its effects with those of a real drug or other intervention, but sometimes for the psychological benefit of the belief of receiving treatment. Placebos are used in clinical trials to blind people to their treatment allocation. Placebos should be indistinguishable from the active intervention to ensure adequate blinding.
  • Power

    The probability of rejecting the null hypothesis when a specific alternative hypothesis is true. In clinical trials, power is the probability that a trial will detect, as statistically significant, an intervention effect of a specified size. Ideally, we want a test to have high power.
  • PPI

    Patient and Public Involvement. In research, PPI takes various forms, from involvement of public contributors in priority setting, representation on committees, and as reviewers. NETS appoint public board and panel members via open competition.
  • Pragmatic trial

    A trial that aims to test a treatment policy in a 'real life' situation, when many people may not receive all of the treatment, and may use other treatments as well.
  • Preclinical study

    Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done.
  • Primary outcome

    The outcome of greatest importance.
  • Primary research

    Experimental studies generating new data (cf. secondary research, which analyses existing data).
  • Prioritisation

    Rigorously examining potential topics for research to identify their importance and where the need for new evidence is greatest.
  • Probability

    The chance or risk of something happening.
  • Protocol

    The plan or set of steps to be followed in a study.