A5V4d

Feverish illness in children
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factors. See also prognostic marker.
Prognostic marker A prognostic factor used to assign patients to categories for a specified
purpose – for example for treatment, or as part of a clinical trial – according to
the likely progression of the disease. For example, the purpose of
randomisation in a clinical trial is to produce similar treatment groups with
respect to important prognostic factors. This can often be achieved more
efficiently if randomisation takes place within subgroups defined by the most
important prognostic factors. Thus if age was very much related to patient
outcome then separate randomisation schemes would be used for different age
groups. This process is known as stratified random allocation.
Prospective study A study in which people are entered into the research and then followed up
over a period of time with future events recorded as they happen. This
contrasts with studies that are retrospective.
Protocol A plan or set of steps that defines appropriate action. A research protocol sets
out, in advance of carrying out the study, what question is to be answered and
how information will be collected and analysed. Guideline implementation
protocols set out how guideline recommendations will be used in practice by
the NHS, both at national and local levels.
Publication bias Studies with statistically significant results are more likely to get published than
those with non-significant results. Meta-analyses that are exclusively based on
published literature may therefore produce biased results. This type of bias can
be assessed by a funnel plot.
Qualitative research Qualitative research is used to explore and understand people’s beliefs,
experiences, attitudes, behaviour and interactions. It generates non-numerical
data, for example a patient’s description of their pain rather than a measure of
pain. In health care, qualitative techniques have been commonly used in
research documenting the experience of chronic illness and in studies about
the functioning of organisations. Qualitative research techniques such as focus
groups and in-depth interviews have been used in one-off projects
commissioned by guideline development groups to find out more about the
views and experiences of patients and carers.
Quality-adjusted life years
(QALYs)
A measure of health outcome that looks at both length of life and quality of life.
QALYs are calculated by estimating the years of life remaining for a patient
following a particular care pathway and weighting each year with a quality of
life score (on a zero to one scale). One QALY is equal to 1 year of life in perfect
health, or 2 years at 50% health, and so on.
Quantitative research Research that generates numerical data or data that can be converted into
numbers, for example clinical trials or the national Census that counts people
and households.
Quasi-experimental study A study designed to test whether a treatment or intervention has an effect on
the course or outcome of disease. It differs from a controlled clinical trial and a
randomised controlled trial in that:
Random allocation or
randomisation
the assignment of patients to treatment and comparison groups is not
done randomly, or patients are not given equal probabilities of selection,
or
the investigator does not have full control over the allocation and/or timing
of the intervention, but nonetheless conducts the study as if it were an
experiment, allocating subjects to treatment and comparison groups.
A method that uses the play of chance to assign participants to comparison
groups in a research study, for example, by using a random numbers table or a
computer-generated random sequence. Random allocation implies that each
individual (or each unit in the case of cluster randomisation) being entered into