Glossary
For additional definitions see the list of further glossaries at
the end of this glossary. A pdf version is available
here.
Absolute effectiveness:
(See Table 4, STP 10)
also absolute effect
Acceptability (related to
indicators): The extent to which the indicator is acceptable
to those being assessed and those undertaking the assessment
AMSTAR (A MeaSurement Tool to
Assess Reviews): A tool designed to assess the quality of
the methods used to conduct a systematic review (see www.biomedcentral.com/1471-2288/7/10)
ART: antiretroviral
therapy. Also referred to as HAART – highly active antiretroviral
therapy
Balance sheet: See
discussion in Table 1, STP 16
Baseline conditions (also known as
baseline characteristics): Values of demographic, clinical
and other variables collected for each participant at the beginning
of a trial, before the intervention is administered
Baseline risk: The risk
(likelihood) of an outcome without implementing an intervention or
at the beginning of a study
Bayesian meta-analysis: An
approach to statistics based on application of Bayes’ theorem that
can be used in single studies or meta-analysis. A Bayesian analysis
uses Bayes' theorem to transform a prior distribution for an
unknown quantity (e.g. an odds ratio) into a posterior distribution
for the same quantity, in light of the results of a study or
studies. The prior distribution may be based on external evidence,
common sense or subjective opinion. Statistical inferences are made
by extracting information from the posterior distribution, and may
be presented as point estimates, and credible intervals (the
Bayesian equivalent of confidence intervals)
Burden of disease: This
refers to the impacts (or burden) of a health problem or condition
(such as hypertension) in an area (such as a country or province),
as measured by mortality, morbidity or other indicators. Burden of
disease is sometimes measured using the ‘disability-adjusted life
year’ or DALY – a time-based measure combining years of life lost
due to premature mortality and years of life lost due to time lived
in states of less than full health
Case survey: A method for
synthesising findings from a number of qualitative studies or to
combine qualitative and quantitative evidence within a single
review. It involves the systematic coding of relevant data from the
included qualitative case studies and the subsequent conversion of
these codes into a quantitative form. This then allow statistical
analysis
CASP (Critical Appraisal Skills
Programme): A UK-based programme that aims to enable
individuals to develop the skills to find and make sense of
research evidence, thereby helping them to put knowledge into
practice (see: www.phru.nhs.uk/pages/PHD/CASP.htm)
Chi-squared test for
homogeneity: A statistical test based on comparison of a
test statistic to a chi-squared distribution used in meta-analyses
to test the statistical significance of heterogeneity (see
‘Heterogeneity’)
CHSRF: Canadian Health
Services Research Foundation
Confidence interval (CI): A
confidence interval is a range around an estimate that conveys how
precise the estimate is; for example an estimate of the risk of an
event occurring or an estimate such as a risk ratio that compares
the risk with and without an intervention. The confidence interval
is a guide to how sure we can be about the quantity we are
interested in. The narrower the range between the two numbers, the
more confident we can be about what the true value is; the wider
the range, the less sure we can be. The width of the confidence
interval reflects the extent to which chance may be responsible for
the observed estimate (with a wider interval reflecting more
chance)
Control group: A group of
participants in a study not receiving a particular intervention,
used as a comparator to evaluate the effects of the intervention
(see ‘Intervention group’)
Controlled before-after
study: A non-randomised study design where a control
population of similar characteristics and performance as the
intervention group is identified. Data are collected before and
after the intervention in both the control and intervention
groups
Controlled trial (See
trial)
Cost-effectiveness
analysis: An economic evaluation in which the costs and
consequences of alternative interventions are expressed cost per
unit of health outcome (e.g. cost per additional stroke prevented)
(for a more detailed discussion see Table 2, STP 5)
Cross-case techniques: A
method for synthesising findings across a number of qualitative
studies or cases
Deflator: A statistical
factor designed to remove the effect of inflation
Differential effectiveness:
Different degrees of effectiveness (or adverse effects) in
different groups or settings
Disaggregated data: Often
data are reported for whole populations or areas. This can be
referred to as aggregate data. In some cases, it may be desirable
and possible to further breakdown or analyse these data to look at
specific groups (such as people over the age of 65 years) or areas
(such as a health district). This can be referred to as
disaggregated data
Effectiveness: The extent
to which a specific intervention, when used under ordinary
circumstances, does what it is intended to do
Egger regression test: A
statistical method for detecting publication bias in a review or
meta-analysis. The test has a similar purpose to that of the funnel
plot (see ‘funnel plot’)
Empirical evidence:
Empirical results based on observation rather than on reasoning
alone
Epidemiology: The study of
the health of populations and communities, not just particular
individuals
Equity considerations:
Attention to how a policy or programme may impact on inequities
(see inequity) (for a more detailed discussion see STP 10)
Estimate of effect: The
observed relationship between an intervention and an outcome
expressed as, for example, a number needed to treat to benefit,
odds ratio, risk difference, risk ratio, standardised mean
difference, or weighted mean difference
Evaluation: a term often
used interchangeably with monitoring. The former usually suggests a
stronger focus on the achievement of results
Evidence-based medicine
(EBM): Evidence-based medicine is the conscientious use of
current best evidence in making decisions about the care of
individual patients or the delivery of health services. The terms
‘evidence-based health care’ and ‘evidence-based practice’ are
often used interchangeably with ‘evidence-based medicine’ (see
STP 1)
Evidence-informed health
policymaking: Evidence-informed health policymaking is an
approach to policy decisions that aims to ensure that decision
making is well-informed by the best available research evidence. It
is characterised by the systematic and transparent access to, and
appraisal of, evidence as an input into the policymaking process
(see STP 1)
Feasibility (related to
indicators): The extent to which valid, reliable and
consistent data are available for collection
Funnel plot: A graphical
display of some measure of study precision plotted against effect
size that can be used to investigate whether there is a link
between study size and treatment effect. One possible cause
of an observed association is reporting bias. The plot is therefore
often used to assess whether publication bias is likely within a
systematic review
GRADE assessment system:
See Table 8, STP
16
Grey literature: Grey
literature is the kind of material that is not published in easily
accessible journals or databases. It includes things like
conference proceedings that include the abstracts of the research
presented at conferences, unpublished theses, and so on
Grounded theory: An
approach used widely within primary qualitative research and
focused on the generation of theory or explanations for social
phenomena, based on empirical data. The method can also be used to
synthesise findings across a number of qualitative studies
Health status: The state of
health of a person or population assessed with reference to
morbidity, impairments, anthropological measurements, mortality,
and indicators of functional status and quality of life
Health system arrangements:
The delivery, financial and governance arrangements within which
clinical or public health programmes and services are provided
Health technology assessment
(HTA): HTA is the systematic evaluation of the properties,
effects and/or other impacts of health care technology. Its primary
purpose is to provide objective information to support healthcare
decisions and policymaking at the local, regional, national and
international levels. HTA reports typically include a range of
economic, social, ethical and legal considerations, as well as a
review of the research evidence about the effectiveness of a
technology. Some HTA reports contain a systematic review that can
be applied in contexts other than the one for which the report was
produced
Hedges: Validated search
strategies to find specific types of single studies
Heterogeneity: 1. Used in a
general sense to describe the variation in, or diversity of,
participants, interventions, and measurement of outcomes across a
set of studies, or the variation in internal validity of those
studies.
2. Used specifically, as statistical heterogeneity, to describe the
degree of variation in the effect estimates from a set of studies.
Also used to indicate the presence of variability among studies
beyond the amount expected due solely to the play of chance
Impact evaluation: An
evaluation that aims to determine whether the observed changes in
outcomes (or “impact”) can be attributed to a particular policy or
programme
Indicator: A quantitative
or qualitative factor or variable that provides a simple and
reliable means to measure achievement, to reflect the changes
connected to an intervention, or to help assess the performance
Indirect evidence: Research
that has not directly compared the options in which we are
interested in the populations in which we are interested, or
measured the important outcomes in which we are interested
Inequity in health: A
difference in health that is not only unnecessary and avoidable
but, in addition, is considered unfair and unjust
Intermediary outcome:
Outcome measures that are not of direct practical importance but
are believed to reflect outcomes that are important; for example,
blood pressure is not directly important to patients but it is
often used as an outcome in clinical trials because it is a risk
factor for stroke and heart attacks. Surrogate endpoints are often
physiological or biochemical markers that can be relatively quickly
and easily measured, and that are taken as being predictive of
important outcomes. They are often used when observation of
important outcomes requires long follow-up
Interrupted time series analysis
or study: A research design that collects observations at
multiple time points before and after an intervention
(interruption). The design attempts to detect whether the
intervention has had an effect significantly greater than the
underlying trend
Intervention: The process
of intervening on people (e.g. clinical interventions), groups or
entities (e.g. health policy or programme options)
Intervention group: A group
of participants in a study receiving a particular policy or
programme option
LMIC: Low- or middle-income
country
MESH term (or headings): An
abbreviation for Medical Subject Headings) Terms used by the United
States National Library of Medicine to index articles in MEDLINE.
The MeSH system has a tree structure in which broad subject terms
branch into a series of progressively narrower subject terms
Meta-analysis: The use of
statistical techniques in a systematic review to integrate the
results of included studies. Sometimes used as a synonym for
systematic reviews, where the review includes a meta-analysis
Meta ethnography: A method
of translating ideas, concepts and metaphors across different
qualitative studies in order to synthesise their findings. The
method draws on the ethnographic approach used in primary
qualitative research
Modifying factor: A factor
or characteristic, such as the size of a health facility that may
change or modify the effect of the proposed causal factor being
studied, such as health worker motivation
Monitoring/performance
monitoring: describes the process of systematically
collecting data to inform policymakers, managers and other
stakeholders whether a new policy or programme is being implemented
in accordance with their expectations
Narrative review: A summary
in words (rather than numerically) of, for example, the effects of
a policy or programme option. Narrative reviews are not always
based on a thorough and reproducible search of the literature for
studies that address the review question
Narrative
summary/synthesis: See ‘Narrative review’. The
approach can be used to synthesise findings across a number of
qualitative studies or to combine qualitative and quantitative
evidence within a single review
Observational study: A
study in which the investigators do not seek to intervene, and
simply observe the course of events. Changes or differences in one
characteristic (e.g. whether or not people received the
intervention of interest) are studied in relation to changes or
differences in other characteristic(s) (e.g. whether or not they
died), without action by the investigator. There is a greater
risk of selection bias than in experimental studies.
See also randomised controlled trial. (Also called non-experimental
study)
OECD: Organisation for
Economic Co-operation and Development
Outcome: A change resulting
from an intervention. In evaluations, a potential consequence of an
intervention that is measured after the intervention has been
implemented, that is used to assess the effects of the
intervention
PICO (Population, Intervention,
Comparison, Outcomes): The acronym, PICO, is used to
summarise the four key components of a review or research question.
In this series we also introduce the acronym, POCO, replacing
intervention with option. POCO similarly summarises the four key
components of a question
Policy brief: See
discussion in STP
13
Policy dialogue: (see
discussion in STP
14)
Policy entrepreneur: People
who seek to initiate policy change
Primary outcome: The
outcome of greatest importance
Primary study: ‘Original
research’ in which data are collected. The term primary study is
sometimes used to distinguish it from a secondary study
(re-analysis of previously collected data), meta-analysis, and
other ways of combining studies (such as economic analysis and
decision analysis). (Also called original study)
Process evaluation: Process
evaluations explore the delivery of a process or programme and the
mechanisms underlying its effects. They verify what the policy or
programme is and whether or not it is delivered as intended to the
target recipients
Process indicator: An
indicator for actions taken or work performed through which inputs,
such as funds, technical assistance and other types of resources
are mobilised to produce specific outputs (see ‘Indicator’).
Processes may also be referred to as ‘activities’ in the results
chain (see Figure 1, STP 18)
Publication bias: A bias
caused by only a subset of all the relevant data being available.
The publication of research can depend on the nature and direction
of the study results. Studies in which an intervention is not
found to be effective are sometimes not published. Because of this,
systematic reviews that fail to include unpublished studies may
overestimate the true effect of an intervention. In addition, a
published report might present a biased set of results (e.g. only
outcomes or sub-groups where a statistically significant difference
was found
Purchasing power parity
(PPP): A criterion for an appropriate exchange rate between
currencies
Qualitative comparative
analysis: A method for synthesising findings from a number
of qualitative studies or to combine qualitative and quantitative
evidence within a single review
Qualitative study:
Qualitative approaches attempt to describe and interpret human
phenomena rather than to measure these. These methods focus on
finding answers to questions centred on social experience,
including the values and perceptions of individuals and groups and
how they experience the world around them, including health
care
Randomised controlled trial
(RCT): An experiment in which two or more interventions,
possibly including a control intervention or no intervention, are
compared by being randomly allocated to participants
Randomised trial: (see
‘randomised controlled trial’)
RCT: Randomised controlled
trial
Realist review/synthesis: A
theory-based method for synthesising findings from a number of
qualitative studies
Relative effectiveness (See
Table 4, STP 10)
Relative reduction: See
relative effectiveness
Results chain: The causal
sequence for a development intervention that stipulates the
necessary sequence to achieve desired objectives – beginning with
inputs, moving through activities and outputs, and culminating in
outcomes, impacts, and feedback. In some agencies, reach is part of
the results chain
Retrospective
analysis/study: An analysis or study planned and conducted
after the dataset has already been collected. For example,
routinely collected data may be analysed retrospectively to
evaluate the effects of a new programme
Risk factor: An aspect of a
person's condition, lifestyle or environment that affects the
probability of occurrence of a disease. For example, cigarette
smoking is a risk factor for lung cancer
Routine data: Data or
information collected as part of normal health service management,
monitoring and evaluation. This may include information on the
prevalence of diseases, on healthcare utilisation, or on service
costs
Stakeholder: A person,
group or organisation that has a legitimate interest in or can be
affected by a health policy or programme
Statistical pooling: The
use of quantitative, statistical methods to combine the findings of
a number of studies of the effects of programme or policy options.
This is also referred to as meta-analysis and may be part of a
systematic review
Statistical significance:
The likelihood that a finding or a result is caused by something
other than just chance (see Table 2, STP 17)
Subgroup analysis: An
analysis in which the intervention effect is evaluated in a defined
subset of the participants in a study or systematic review, or in
complementary subsets, such as by sex or in age categories
Surrogate outcome: Outcome
measures that are not of direct practical importance but are
believed to reflect outcomes that are important; for example, blood
pressure is not directly important to patients but it is often used
as an outcome in clinical trials because it is a risk factor for
stroke and heart attacks. Surrogate endpoints are often
physiological or biochemical markers that can be relatively quickly
and easily measured, and that are taken as being predictive of
important outcomes. They are often used when observation of
important outcomes requires long follow-up
Systematic review:
Summaries of research evidence that address a clearly formulated
question using systematic and explicit methods to identify, select,
and critically appraise relevant research, and to collect and
analyse data from the studies that are included in the review
Thematic analysis: A method
for synthesising findings from a number of qualitative studies. It
includes identifying key themes in the included studies and then
summarising the evidence within these themes or categories
Trial: The term ‘trial’ is
sometimes used to refer to randomised controlled trials (RCTs). The
term may also be used to refer to quasi-randomised trials (e.g.
where alternation (every other person or group) is used to allocate
people, rather than randomisation) (Also called controlled
trial)
Validity (related to
indicators): The extent to which an indicator accurately
measures what it purports to measure
Further glossaries relevant to
evidence-informed health policymaking
Canadian Health Services Research Foundation Glossary of knowledge
exchange terms as used by the Foundation:
http://www.chsrf.ca/PublicationsAndResources/ResourcesForResearchers/KEYS/GlossaryOfKnowledgeExchangeTerms.aspx
Canadian Institutes of Health Research KT Clearinghouse
Glossary: http://ktclearinghouse.ca/glossary
Cochrane Collaboration Glossary of Cochrane
Collaboration and research terms: http://www.cochrane.org/glossary
Global Forum for Health Research Glossary: http://www.globalforumhealth.org/Glossary
Health Economics Information Resources Glossary of
frequently encountered terms in health economics: http://www.nlm.nih.gov/nichsr/edu/healthecon/glossary.html
NHS Evidence Glossary of health knowledge management
terms: https://www.evidence.nhs.uk/document?ci=http%3A%2F%2Farms.evidence.nhs.uk%2Fresources%2FHub%2F21267&ReturnUrl=%2Fsearch%3Fq%3Devidence%2Bglossary%2Bhealth%2Bknowledge%2Bmanagement
Public Health Agency of Canada: http://cbpp-pcpe.phac-aspc.gc.ca/glossary/all_terms-eng.html
WhatisKT: http://whatiskt.wikispaces.com/KT+Terms
This page was last updated November 2011.