The difference in the risk of an event between two groups (one subtracted from the other) in a comparative study.

Summary of a study, which may be published alone or as an introduction to a full scientific paper.

A flow chart of the clinical decision pathway described in the guideline, where decision points are represented with boxes, linked with arrows.

The process used to prevent advance knowledge of group assignment in a randomised controlled trial (RCT). The allocation process should be impervious to any influence by the individual making the allocation, by being administered by someone who is not responsible for recruiting participants.

Product intended to prevent faecal leakage from the anus.

Surgical repair of the anal sphincter.

An operation to bring the appendix onto the abdominal wall to allow a catheter to be inserted into the colon (also known as Malone operation). Liquids and laxatives can be instilled to wash out the colon.

The degree to which the results of an observation, study or review are likely to hold true in a particular clinical practice setting.

Sub-section of individuals within a study who receive one particular intervention, for example placebo arm.

A cuff made of silicone that encircles the anus and contains liquid that is transferred between a reservoir and the cuff. This either opens or occludes the anal canal.

Statistical relationship between two or more events, characteristics or other variables. The relationship may or may not be causal.

See ‘Clinical audit’.

The results of an economic evaluation using the best point estimate for each model parameter. This contrasts with the term sensitivity analysis.

The initial set of measurements at the beginning of a study (after run-in period where applicable), with which subsequent results are compared.

Baseline assessment includes structured assessment, clinician examination and patient reporting of symptoms.

Systematic (as opposed to random) deviation of the results of a study from the ‘true’ results that is caused by the way the study is designed or conducted.

Use of equipment to amplify and display bodily functions that are normally subconscious or automatic, with the aim of improving that function.

Biocompatible material injected into the body with the aim of improving function.

Keeping the study participants, caregivers, researchers and outcome assessors unaware about the interventions to which the participants have been allocated in a study

Rating of stool consistency on a 7 point scale from hard to liquid.

Someone other than a health professional who is involved in caring for a person with a medical condition.

Comparative observational study in which the investigator selects individuals who have experienced an event (for example, developed a disease) and others who have not (controls), and then collects data to determine previous exposure to a possible cause.

Report of a number of cases of a given disease, usually covering the course of the disease and the response to treatment. There is no comparison (control) group of patients.

A scale from 0–20 where 0 = perfect continence and 20 = complete incontinence.

A quality improvement process that seeks to improve patient care and outcomes through systematic review of care against explicit criteria and the implementation of change.

The extent to which an intervention is active when studied under controlled research conditions.

The extent to which an intervention produces an overall health benefit in routine clinical practice.

The effect that a guideline recommendation is likely to have on the treatment or treatment outcomes, of the target population.

In guideline development, this term refers to the questions about treatment and care that are formulated to guide the development of evidence-based recommendations.

A healthcare professional providing direct patient care, for example doctor, nurse or physiotherapist.

A regularly updated electronic collection of evidence-based medicine databases, including the Cochrane Database of Systematic Reviews.

A systematic review of the evidence from randomised controlled trials relating to a particular health problem or healthcare intervention, produced by the Cochrane Collaboration. Available electronically as part of the Cochrane Library.

A retrospective or prospective follow-up study. Groups of individuals to be followed up are defined on the basis of presence or absence of exposure to a suspected risk factor or intervention. A cohort study can be comparative, in which case two or more groups are selected on the basis of differences in their exposure to the agent of interest.

Co-existence of more than one disease or an additional disease (other than that being studied or treated) in an individual.

Operation to divert bowel contents through the abdominal wall via a ‘stoma’. Usually a bag is worn to collect faeces.

Similarity of the groups in characteristics likely to affect the study results (such as health status or age).

See ‘Concordance’.

The extent to which a person adheres to the health advice agreed with healthcare professionals. May also be referred to as ‘adherence’ or ‘compliance’.

A range of values for an unknown population parameter with a stated ‘confidence’ (conventionally 95%) that it contains the true value. The interval is calculated from sample data, and generally straddles the sample estimate. The ‘confidence’ value means that if the method used to calculate the interval is repeated many times, then that proportion of intervals will actually contain the true value.

In a study, confounding occurs when the effect of an intervention on an outcome is distorted as a result of an association between the population or intervention or outcome and another factor (the ‘confounding variable’) that can influence the outcome independently of the intervention under study.

Techniques that aim to reach an agreement on a particular issue. Formal consensus methods include Delphi and nominal group techniques, and consensus development conferences. In the development of clinical guidelines, consensus methods may be used where there is a lack of strong research evidence on a particular topic. Expert consensus methods will aim to reach agreement between experts in a particular field.

Non-surgical treatment

A group of patients recruited into a study that receives no treatment, a treatment of known effect, or a placebo (dummy treatment) - in order to provide a comparison for a group receiving an experimental treatment, such as a new drug.

A study testing a specific drug or other treatment involving two (or more) groups of patients with the same disease. One (the experimental group) receives the treatment that is being tested, and the other (the comparison or control group) receives an alternative treatment, a placebo (dummy treatment) or no treatment. The two groups are followed up to compare differences in outcomes to see how effective the experimental treatment was. A CCT where patients are randomly allocated to treatment and comparison groups is called a randomised controlled trial.

A type of economic evaluation where both costs and benefits of healthcare treatment are measured in the same monetary units. If benefits exceed costs, the evaluation would recommend providing the treatment.

A type of economic evaluation where various health outcomes are reported in addition to cost for each intervention, but there is no overall measure of health gain.

An economic study design in which consequences of different interventions are measured using a single outcome, usually in ‘natural’ units (for example, life-years gained, deaths avoided, heart attacks avoided, cases detected). Alternative interventions are then compared in terms of cost per unit of effectiveness.

A form of cost-effectiveness analysis in which the units of effectiveness are quality-adjusted life-years (QALYs).

A systematic way of reaching decisions, based on evidence from research. This evidence is translated into probabilities, and then into diagrams or decision trees which direct the clinician through a succession of possible scenarios, actions and outcomes. It can be used to estimate effectiveness or cost-effectiveness.

X-ray to examine the structure of the anorectum and its function during bowel emptying

Costs and perhaps benefits incurred today have a higher value than costs and benefits occurring in the future. Discounting health benefits reflects individual preference for benefits to be experienced in the present rather than the future. Discounting costs reflects individual preference for costs to be experienced in the future rather than the present.

An intervention is said to be dominant if there is an alternative intervention that is both less costly and more effective.

The prescribed amount of a drug to be taken, including the size and timing of the doses.

A study in which neither the subject (patient) nor the observer (investigator/clinician) is aware of which treatment nor intervention the subject is receiving. The purpose of blinding is to protect against bias.

Urinary and faecal incontinence.

A participant who withdraws from a clinical trial before the end.

Operation which transposes the gracilis muscle from the leg and wraps it around the anus to form a new sphincter. An implanted electrical stimulator keeps the muscle contracted and thus the anus closed.

Comparative analysis of alternative health strategies (interventions or programmes) in terms of both their costs and consequences.

The observed association between interventions and outcomes or a statistic to summarise the strength of the observed association.

See ‘Clinical effectiveness’.

See ‘Clinical efficacy’.

Non-emergency procedure

Use of electrical current to produce a contraction of a striated (voluntary) muscle.

Ultrasound images of the anal sphincter taken using an intraanal probe.

Use of an endoscope to image the interior of the bowel.

The study of a disease within a population, defining its incidence and prevalence and examining the roles of external influences (for example, infection, diet) and interventions.

Information on which a decision or guidance is based. Evidence is obtained from a range of sources including randomised controlled trials, observational studies, expert opinion (of clinical professionals and/or patients).

A table summarising the results of a collection of studies which, taken together, represent the evidence supporting a particular recommendation or series of recommendations in a guideline.

Explicit standards used to decide which studies should be excluded from consideration as potential sources of evidence.

Criteria that define who is not eligible to participate in a clinical study.

See ‘Consensus methods’.

If Option A is both more clinically effective than Option B and has a lower cost per unit of effect, when both are compared with a do-nothing alternative then Option A is said to have extended dominance over Option B. Option A is therefore more efficient and should be preferred, other things remaining equal.

Voluntary (striated muscle) portion of the anal sphincter.

In data analysis, predicting the value of a parameter outside the range of observed values.

Adhesive bag or rectal tube with a bag attached used to collect faeces.

The term used when there is large amount of hard faeces in the rectum.

The term used to describe the presence of a large amount of faeces in the rectum with stool of any consistency.

Observation over a period of time of an individual, group or initially defined population whose appropriate characteristics have been assessed in order to observe changes in health status or health-related variables.

The extent to which the results of a study based on measurement in a particular patient population and/or a specific context hold true for another population and/or in a different context. In this instance, this is the degree to which the guideline recommendation is applicable across both geographical and contextual settings. For instance, guidelines that suggest substituting one form of labour for another should acknowledge that these costs might vary across the country.

Transposition of one or both gluteal muscles from the buttock to form a new anal sphincter. May additionally have an implanted electrical stimulator (‘stimulated gluteoplasty’).

See ‘Reference standard’.

See ‘Dynamic graciloplasty’

See ‘Dynamic graciloplasty’

Adverse effects of an intervention.

The study of the allocation of scarce resources among alternative healthcare treatments. Health economists are concerned with both increasing the average level of health in the population and improving the distribution of health.

A combination of an individual’s physical, mental and social well-being; not merely the absence of disease.

A supposition made as a starting point for further investigation.

Explicit criteria used to decide which studies should be considered as potential sources of evidence.

The analysis of additional costs and additional clinical outcomes with different interventions.

The difference in the mean costs in the population of interest divided by the differences in the mean outcomes in the population of interest.

In epidemiology and related sciences, this word usually means a rating scale, for example, a set of numbers derived from a series of observations of specified variables. Examples include the various health status indices, and scoring systems for severity or stage of cancer.

The defined use of a technology as licensed by the Medicines and Healthcare products Regulatory Agency (MHRA).

Initial management involves adjusting the patient’s fluid intake, diet and medication separately and to ensure they complement each other.

Involuntary (smooth muscle) portion of the anal sphincter.

The degree to which the results of a study are likely to approximate the ‘truth’ for the participants recruited in a study (that is, are the results free of bias?). It refers to the integrity of the design and is a prerequisite for applicability (external validity) of a study’s findings. See ‘External validity’.

Healthcare action intended to benefit the patient, for example, drug treatment, surgical procedure, psychological therapy.

Describes timing of anything that happens during a surgical procedure.

The total number of days a patient stays in hospital.

This involves plicating the muscles of the pelvic floor above the anal canal, between the rectum and the vagina (anterior levatorplasty) or posterior to the anal sphincter (post anal repair)

See ‘Antegrade continent enema (ACE) operation’

Measurement of anal sphincter pressures.

All products, except medicines, used in healthcare for the diagnosis, prevention, monitoring or treatment of illness or handicap.

The Executive Agency of the Department of Health protecting and promoting public health and patient safety by ensuring that medicines, healthcare products and medical equipment meet appropriate standards of safety, quality, performance and effectiveness, and are used safely.

A statistical technique for combining (pooling) the results of a number of studies that address the same question and report on the same outcomes to produce a summary result. The aim is to derive more precise and clear information from a large data pool. It is generally more reliably likely to confirm or refute a hypothesis than the individual trials.

Summary of findings given as a written description.

A replacement for the sphincter when repair is not possible or has failed. See also ‘Dynamic graciloplasty’ and ‘ Artificial anal sphincter ‘

FI secondary neurological disease to or injury

Implanted electrical stimulator to act in place of natural neurological impulses

Retrospective or prospective study in which the investigator observes the natural course of events with or without control groups; for example, cohort studies and case–control studies.

A measure of treatment effectiveness. The odds of an event happening in the treatment group, expressed as a proportion of the odds of it happening in the control group. The ‘odds’ is the ratio of events to non-events.

Measure of the possible results that may stem from exposure to a preventive or therapeutic intervention. Outcome measures may be intermediate endpoints or they can be final endpoints. See ‘Intermediate outcome’.

The probability that an observed difference could have occurred by chance, assuming that there is in fact no underlying difference between the means of the observations. If the probability is less than 1 in 20, the P value is less than 0.05; a result with a P value of less than 0.05 is conventionally considered to be ‘statistically significant’.

A process where research is scrutinised by experts that have not been involved in the design or execution of the studies.

Muscles extending under the internal organs from the pubic bone at the front to the coccyx (tail bone) at the back.

The period from admission through surgery until discharge, encompassing pre-operative and post-operative periods.

An inactive and physically identical medication or procedure used as a comparator in controlled clinical trials.

A beneficial (or adverse) effect produced by a placebo and not due to any property of the placebo itself.

Surgical procedure for reducing the size of a hollow structure by taking folds or tucks in its walls

Percutaneous Tibial Nerve Stimulation

Plication of the pelvic floor muscles behind the anus

Pertaining to the period after patients leave the operating theatre, following surgery.

Pertaining to the period before surgery commences.

Healthcare delivered to patients outside hospitals. Primary care covers a range of services provided by GPs, nurses and other healthcare professionals, dentists, pharmacists and opticians.

A probable course or outcome of a disease. Prognostic factors are patient or disease characteristics that influence the course. Good prognosis is associated with low rate of undesirable outcomes; poor prognosis is associated with a high rate of undesirable outcomes.

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.

The back portion of the pelvic floor muscles, around the rectum and anal canal

Research concerned with subjective outcomes relating to social, emotional and experiential phenomena in health and social care.

See ‘Health-related quality of life’.

An index of survival that is adjusted to account for the patient’s quality of life during this time. QALYs have the advantage of incorporating changes in both quantity (longevity/mortality) and quality (morbidity, psychological, functional, social and other factors) of life. Used to measure benefits in cost-utility analysis. The QALYs gained are the mean QALYs associated with one treatment minus the mean QALYs associated with an alternative treatment.

Research that generates numerical data or data that can be converted into numbers, for example clinical trials or the national Census which counts people and households.

An abridged version of NICE guidance, which presents the key priorities for implementation and summarises the recommendations for the core clinical audience.

Allocation of participants in a research study to two or more alternative groups using a chance procedure, such as computer-generated random numbers. This approach is used in an attempt to ensure there is an even distribution of participants with different characteristics between groups and thus reduce sources of bias.

A comparative study in which participants are randomly allocated to intervention and control groups and followed up to examine differences in outcomes between the groups.

Descent of the rectum outside the body through the anal canal.

An agreed standard, for example for a test or treatment, against which other interventions can be compared.

The number of times more likely or less likely an event is to happen in one group compared with another (calculated as the risk of the event in group A/the risk of the event in group B).

The degree of agreement exhibited when a measurement is repeated under identical conditions. Reliability refers to the degree to which the results obtained by a measurement procedure can be replicated.

The brief given by the Department of Health and Welsh Assembly Government at the beginning of the guideline development process. This defines core areas of care that the guideline needs to address.

The likely impact in terms of finance, workforce or other NHS resources.

A retrospective study deals with the present/past and does not involve studying future events. This contrasts with studies that are prospective.

An article that summarises the evidence contained in a number of different individual studies and draws conclusions about their findings. It may or may not be systematically researched and developed.

This technique involves stimulating the sacral nerves, usually S3 or S4. Its main advantage is a trial period of temporary stimulation that only involves simple insertion of stimulating wires into the back. If this is successful, the patient can have an implantable stimulator to modulate sacral nerve function and improve continence.

Radio frequency ablation of tissues with the aim of tightening.

A systematic bias in selecting participants for study groups, so that the groups have differences in prognosis and/or therapeutic sensitivities at baseline. Randomisation (with concealed allocation) of patients protects against this bias.

Explicit standards used by guideline development groups to decide which studies should be included and excluded from consideration as potential sources of evidence.

The proportion of relevant studies identified by a search strategy expressed as a percentage of all relevant studies on a given topic. It describes the comprehensiveness of a search method (that is, its ability to identify all relevant studies on a given topic). Highly sensitive strategies tend to have low levels of specificity and vice versa.

A means of representing uncertainty in the results of economic evaluations. Uncertainty may arise from missing data, imprecise estimates or methodological controversy. Sensitivity analysis also allows for exploring the generalisability of results to other settings. The analysis is repeated using different assumptions to examine the effect on the results.

One-way simple sensitivity analysis (univariate analysis): each parameter is varied individually in order to isolate the consequences of each parameter on the results of the study.

Multi-way simple sensitivity analysis (scenario analysis): two or more parameters are varied at the same time and the overall effect on the results is evaluated.

Threshold sensitivity analysis: the critical value of parameters above or below which the conclusions of the study will change are identified.

Probabilistic sensitivity analysis: probability distributions are assigned to the uncertain parameters and are incorporated into evaluation models based on decision analysis.

Assessment by a health care professional with specialist training.

Management by a health care professional with specialised training.

See anal sphincter repair.

Those with an interest in the use of a technology under appraisal or a guideline under development. Stakeholders include manufacturers, sponsors, healthcare professionals, and patient and carer groups.

The ability to demonstrate an association when one exists. Power is related to sample size; the larger the sample size, the greater the power and the lower the risk that a possible association could be missed.

A generic term to describe methods used for summarising (comparing and contrasting) evidence into a clinically meaningful conclusion in order to answer a defined clinical question. This can include systematic review (with or without meta-analysis), qualitative and narrative summaries.

Research that summarises the evidence on a clearly formulated question according to a pre-defined protocol using systematic and explicit methods to identify, select and appraise relevant studies, and to extract, collate and report their findings. It may or may not use statistical meta-analysis.

The time span used in the NICE appraisal which reflects the period over which the main differences between interventions in health effects and use of healthcare resources are expected to be experienced, and taking into account the limitations of supportive evidence.

Surgical tightening of the pelvic floor in front of and behind the anus.

Assigning a participant to a particular arm of the trial.

The choices of intervention available.

The use of sound waves to image the deep structures of the body.

See Cleveland clinic score