Adverse effect Collective adverse events.
Adverse event An adverse event is a single incident that occurs during or after exposure to a drug or other intervention and which may or may not be caused by the intervention.
Allocation bias Bias resulting from a systematic difference (other than the intervention) between experimental and control groups in a clinical trial. Allocation bias can be avoided by allocating individuals to groups using a concealed random mechanism.
Allocation concealment The process used to prevent foreknowledge of group assignment in a randomised controlled trial. Inadequate concealment of allocation may lead to selection bias.
Attrition bias Bias resulting from systematic differences between comparison groups in withdrawals or exclusions of participants from the results of a study.
Before-and-after study A study design where a group is studied before and after an intervention.   Interpretation of the effect of the intervention is often difficult as the change may have been due to factors other than the intervention.
Bias A systematic error or deviation in results or inferences. See also selection bias; performance bias; attrition bias; detection bias.
Bibliographic databases Databases that provide descriptive records of items such as books and articles.
Bibliographic software Computer software that assists with the organisation of bibliographic references. There are many different packages (e.g. EndNote, Reference Manager), but most will allow for the import of references from bibliographic databases and the automated production of reference lists.
Blinding Keeping secret group assignment (e.g. to treatment or control) from the study participants, investigators or outcome assessors.
Boolean operator Boolean operators are used to combine terms when conducting electronic searches. Examples include “AND” (used to narrow a search), “OR” (used to broaden a search) and “NOT” (used to exclude terms from a search).
Case control study A study that compares people with a specific disease or outcome of interest (cases) to people from the same population without that disease or outcome (controls), and which seeks to find associations between the outcome and prior exposure to particular risk factors.
Case series A study reporting observations on a series of individuals, usually all receiving the same intervention, with no control group.
Causation The “causal relationship between conduct and result”. That is to say that causation provides a means of connecting conduct with a resulting effect.
Cluster randomisation Randomisation of clusters of individuals (e.g. general practices, schools) rather than individuals themselves.
Cohort study An epidemiological study in which groups of individuals are identified who vary in their exposure to an intervention or hazard, and are then followed to assess outcomes.
CONSORT statement A set of guidelines for the reporting of randomised controlled trials.
Comparator In a controlled trial, the intervention (which could include placebo or no treatment) with which the intervention of interest is compared.
Complex intervention An intervention that involves a number of separate elements that seem essential to the proper functioning of the intervention although the active ingredient of the intervention that is effective is difficult to specify
Conceptual mapping In narrative synthesis, the use of visual methods to help to construct groupings of, and relationships between, ideas and/or concepts. Closely related to idea webbing.
Conceptual triangulation In narrative synthesis, the use of a combination of different perspectives and/or methods to study a particular concept.
Confidence interval The range within which the “true” value (e.g. size of effect of an intervention) is expected to lie with a given degree of probability (e.g. 95% or 99%). Note: Confidence intervals represent the probability of random errors, but not systematic errors (bias).
Confounding A situation in which a measure of the effect of an intervention or exposure is distorted because of the association of exposure with other factor(s) that influence the outcome under investigation.
Content analysis A set of procedures for collecting and organizing non-structured information. This approach makes it easier for researchers to systematically and objectively analyse the data and make inferences about the population of interest.
Continuous outcomes Outcomes related to variables with a potentially infinite number of possible values along a continuum, for example weight and blood pressure.
Control group In a controlled trial, the arm that acts as a comparator for one or more experimental interventions. In a case-control study, the group without the disease or outcome of interest.
Controlled trial A clinical trial with a control group.
Correlation The degree to which two or more attributes or measurements on the same group of elements show a tendency to vary together.
Cost-effectiveness analysis An economic analysis that converts effects into health terms and describes the costs for some additional health gain (e.g. cost per additional stroke prevented).
Cross-over trial A type of clinical trial comparing two or more interventions in which all the participants receive all the interventions but the order of receipt is determined by randomisation.
Cross-sectional study A study that examines the relationship between diseases (or other health related characteristics) and other variables of interest as they exist in a defined population at a particular time.
Detection bias Bias caused by systematic differences between comparison groups in how outcomes are ascertained, diagnosed or verified.
Double-blind In clinical trials, a study design by which neither the participants nor the investigators (outcome assessors) are aware of which intervention the participants are given.
Dual-diagnosis An individual presenting with both mental health issues and substance misuse.
Effectiveness The extent to which a specific intervention, when used under ordinary circumstances, does what it is intended to do.
Estimate of effect In studies of the effects of healthcare, the observed relationship between an intervention and an outcome expressed as, for example, a number needed to treat, odds ratio, risk difference, relative risk, standardised mean difference, or weighted mean difference.
Evidence based policing An approach to the practice of policing that involves Integrating individual professional expertise with the best available research evidence.
Free text terms In literature searching, the use of everyday words and phrases, as opposed to index terms, to search bibliographic databases.
Frequent Caller NYP define a frequent caller to be any individual who has called more than 10 times within a 6 month period. To be classed as a frequent caller the caller must have an incident created within the Police’s command and control system (Aspire).
Generalisability The degree to which the results of a study hold true in other settings. See also validity.
Grey literature A general term for the kind of material that is not published in an easily accessible form or listed in standard bibliographic databases, for example conference proceedings, internal reports theses and some books.
Hand searching The process of searching a journal page by page to identify relevant articles.
Hazard ratio An estimate of effect used in studies where the main interest is in time to the occurrence of an event.
Heterogeneity In systematic reviews heterogeneity refers to variability or differences in estimates of effect between studies. A distinction is sometimes made between “statistical heterogeneity” (differences in the reported effects) and “methodological heterogeneity” (differences in study design).
Hierarchy of evidence


A hierarchy of study designs based on their internal validity, with well- designed systematic reviews and randomised trials at the top and observational studies and case series lower down.
Homogeneity In systematic reviews, the degree of similarity between the studies included in a review.
Indexing term(s) A word or words used to describe the subject of, for example, a journal article. They are designed to make searching easier and more effective. Ideally these terms will be assigned from a controlled vocabulary, for example MeSH. See also MeSH.
Intention to treat (ITT) An analysis in which all the participants in a trial are analysed according to the intervention to which they were allocated, whether they received it or not.
Intervention group A group of participants in a study receiving a particular health care intervention.
Key word(s) A word or words used to describe the subject of, for example, a journal article. They are designed to make searching easier and more effective. Ideally these terms will be assigned from a controlled vocabulary, for example MeSH. See also MeSH.
Language bias Bias in a systematic review resulting from the exclusion of items not written in a particular language or languages.
Language restrictions The deliberate restriction of search results to particular languages. Results in language bias.
Literature search For a systematic review this should be a systematic search for information on a given topic. Can include searches of bibliographic databases, websites, handsearching of journals and books, citation searching and reference checking.
Logic model (Also known as a logical framework, theory of change, or program matrix) is a tool used by funders, managers, and evaluators of programs to evaluate the effectiveness of a program.
Medical Subject Heading (MeSH) MeSH is the controlled vocabulary indexing system used by the National Library of Medicine for indexing articles on Medline. It is used on some other electronic bibliographic databases.

See also Indexing term; Keyword.

Meta-analysis The use of statistical techniques in a systematic review to integrate the results of included studies and obtain a pooled estimate of effect.
Meta-regression A statistical technique used to explore the relationship between study characteristics and study results in a systematic review.
Niche Local police records management system, used to manage the post-incident investigation of cases. Links details of people, addresses, vehicles, intelligence etc.
Number needed to treat/harm (NNT/NNH) An estimate of how many people need to receive a treatment before one more person would experience a beneficial or a harmful outcome, respectively. Also referred to as number needed to treat for benefit (NNTB) and number needed to treat for harm (NNTH).
Observational study A study in which the investigators do not seek to intervene, and simply observe the course of events.
Odds ratio The ratio of the odds of an event in one group (e.g. the experimental (intervention) group) to the odds of an event in another (e.g. the control group).
Performance bias Bias resulting from systematic differences in care provided apart from the intervention being evaluated.
Piloting The process of testing a procedure on a small scale before introducing it into practice, e.g. testing a data extraction form on a small sample of studies to identify any problems and inconsistencies between reviewers.
Placebo An intervention without specific biological activity in the condition being treated, usually administered to compare its effects with those of an active intervention.
Police Community Support Officers (PCSO) Members of the Safer Neighbourhood Policing Team, working within communities (NYP 2016). PCSOs have different roles in different forces including: dealing with minor offences, early intervention to deter people from committing offences, support for front-line officers, house-to-house enquiries, guarding crime scenes, crime prevention advice (College of Policing, 2016).
Police Constables (PC) Officers, who respond to 999 calls, investigate volume crime or take initial action at critical incidents. Constables also work within neighbourhood teams to target long term problems (Mental Health Cop, 2016).
Police Inspector Senior operational officers who oversee responses to crucial incidents and all officers that are on duty (Mental Health Cop, 2016).
Police Sergeant Supervise teams of officers, oversee police operations, volume crime investigations, demand management issues and take initial control of critical indents. Typically at least 2-3 sergeants in each borough are on duty at any time (Mental Health Cop, 2016).
Population A well-defined collection of individuals known to have similar characteristics. All individuals or objects within a certain population usually have a common, binding characteristic or trait.
Post-test A test given after completion of an instructional program or segment and often used in conjunction with a pre-test to measure achievement and the effectiveness of the program.
Pre-test A preliminary test or trial.
Primary outcome The outcome of greatest importance for a clinical study or systematic review.
Primary study An “original research” study in which data are first collected. The term primary research is sometimes used to distinguish such studies from “secondary research” (reanalysis of previously collected data), meta-analysis, and other ways of combining studies (such as economic analysis and decision analysis).
Process evaluation Looks at the actual development and implementation of a particular program. It establishes whether you’ve hit quantifiable targets and implemented strategies as planned. It’s typically done at the end of the project and it looks at the program from start to finish, assessing cause-and-effect relationships between the program components and outcomes.
Proxy outcome An outcome (often a physiological or biochemical marker) that is believed to be related to an important clinical outcome of interest and is used in research studies because it is quicker, cheaper or easier to measure.
Publication bias Bias arising from the fact that studies without statistically significant results are more likely to remain unpublished than those showing an intervention to be effective. As a result, systematic reviews that fail to search for unpublished studies may omit relevant research. Publication bias may lead systematic reviews to overestimate the effect of an intervention.
Qualitative research Research that concentrates on the investigation of definitions, concepts and issues, often performed through interview unrestricted by structure, and reported in terms of words or descriptions.
Qualitative synthesis Sometimes called a qualitative systematic review, systematically searches for research on a topic, and draws the findings from individual studies together.
Quality threshold In systematic reviews, restricting inclusion to studies that meet predefined criteria related to quality (validity).
Quantitative research Research that concentrates on describing and analysing phenomena by using numerical data and empirical models.
Randomisation The process of randomly allocating participants to one of the groups of a randomised controlled trial, including the method used to ensure that allocation is truly random.
Randomised controlled trial (RCT) An experiment in which investigators randomly allocate participants into intervention groups to receive or not to receive one or more interventions that are being compared.
Raw data Data that have not been processed or transformed for analysis.
Research design Refers to the overall strategy that you choose to integrate the different components of the study in a coherent and logical way, thereby, ensuring you will effectively address the research problem; it constitutes the blueprint for the collection, measurement, and analysis of data.
Research question A statement about an area of concern, a condition to be improved upon, a difficulty to be eliminated, or a troubling question that exists in scholarly literature, in theory, or in practice that points to the need for meaningful understanding and deliberate investigation.
Sample frame In statistics, a sampling frame is the source material or device from which a sample is drawn. It is a list of all those within a population who can be sampled, and may include individuals, households or institutions.
Sample size calculation A calculation performed when planning a clinical study to determine the number of participants needed to ensure a given probability of detecting an effect of a given magnitude if it exists.
Search interface The means by which a user can interrogate a database. Interfaces vary in complexity. Some consist merely of a text box in which a limited number of words can be entered. Others are more complex and allow the searcher to create complex searches. See also database host.
Search strategy A report of the exact terms and their combinations used to search a bibliographic database.
Secondary outcome An outcome used in a clinical study or systematic review that is defined in advance as being less important than the primary outcome.
Selection bias 1. Bias caused by systematic differences between comparison groups in prognosis or responsiveness to treatment.

2. Bias caused by systematic differences between those who are selected for a study and those who are not. This affects the generalisability (external validity) of a study but not its (internal) validity.

3. In systematic reviews, bias arising from the way in which studies were selected for inclusion. Publication bias is an example of this type of selection bias.

Stakeholder In systematic reviews a person or group with an interest in or potentially affected by the results of the review.
Standardised mean difference The difference between two means divided by an estimate of the within-group standard deviation. It is used to combine results from studies using different ways of measuring the same concept, e.g. mental health.
Statistical significance Data worthy of attention; importance.
Statistical power In studies of the effectiveness of healthcare interventions, power is a measure of the probability of avoiding a false negative conclusion that an intervention is not effective when in truth it is effective.
Street Triage Innovative model of collaboration between police and Mental Health services to provide a rapid response to mentally vulnerable people in contact with police.
Subgroup analysis In a clinical study or systematic review, an analysis in which the effect of the intervention is evaluated in a defined subset or subsets of participants.
Summary data Data that have been aggregated for presentation or analysis, for example numbers of events in each group in a clinical trial.
Systematic review A research study that collects and looks at multiple studies. Researchers use methods that are determined before they begin to frame one or more questions, then they find and analyse the studies that relate to that question.
Tag Coding used on the initial STORM incident to indicate the type of incident being reported (e.g. Mental Health, Triage, S136, Domestic, Concern for safety etc.)
Thematic analysis A method used in the analysis of qualitative data to systematically identify the main, recurrent and/or most important themes and/or concepts across multiple responses.
Theory of change A comprehensive description and illustration of how and why a desired change is expected to happen in a particular context. It is focused in particular on mapping out or “filling in” what has been described as the “missing middle” between what a program or change initiative does (its activities or interventions) and how these lead to desired goals being achieved. It does this by first identifying the desired long-term goals and then works back from these to identify all the conditions (outcomes) that must be in place (and how these related to one another causally) for the goals to occur. These are all mapped out in an Outcomes Framework.
Time preferences The predilection of an individual (or a society) for the use of resources in the present rather than in the future.
Triangulation A research strategy in which the researcher observes the same variable or phenomenon with multiple sources, measures, and methods.
Update searching The re-running of a literature search to capture material that has become available since the original search was conducted. May involve re-writing search strategies to take account of changes in terminology and database indexing.
Validity (of a measurement) The degree to which a measurement truly measures what it purports to measure.
Validity (of a study) The degree to which a result of a study is likely to be true and free of bias (systematic errors) and hence the degree to which inferences drawn from the study are likely to be justified. Validity in this sense is synonymous with internal validity. See also external validity.
Warning Markers Risk markers applied to individuals records on Niche (e.g. Mental Disorder, Suicidal, Self-harm, violent, Ailment, contagious etc.)
Weighting In meta-analysis, the relative contribution of each individual study to the overall result and/or the method used to determine this. Studies are often weighted by the inverse of the variance of their measure of effect so that studies with more precise results make a relatively greater contribution.
Worst/best case analysis (or analyses of extremes) In economic evaluations, a sensitivity analysis using extreme values for the input data to investigate the outcome of the economic evaluation in the extreme case. A pessimistic or optimistic outcome is generated.



ACP Alternative Care Pathways.
A&E Accident & Emergency Department (Emergency Department).
AMHP Approved Mental Health Professional.
ASD Autistic Spectrum Disorder.
BME Black and Minority Ethnic.
CAMHS Child & Adolescent Mental Health Services.
CAS Crisis Access Service (linked to the Single Point of Access in York).
CCG Clinical Commissioning Group.
CONSORT Consolidated Standards of Reporting Trials
CPA Care Programme Approach.
CMHT Community Mental Health Team.
CYC City of York Council.
CYPS Children & Young Peoples Services.
DD Dual Diagnosis.
ED Emergency Department (formerly A&E).
EDT Emergency Duty Team.
Entity A record of either a person, vehicle or address on Niche.
FCR Force Control Room.
GP General Practitioner.
HaRDCCG Harrogate and Rural District Clinical Commissioning Group.
HBPOS Health Based Place Of Safety.
HRWCCG Hambleton, Richmondshire & Whitby Clinical Commissioning Group.
IHTT Intensive Home Treatment Team (Crisis Service).
ITT Intention to treat.
LD Learning Disability.
LR Likelihood ratio.
MDT Multi-disciplinary Team.
MFH Missing From Home.
MeSH Medical Subject Heading.
MH Mental Health.
MHA Mental Health Act.
MHFA Mental Health First Aid.
MOOSE Meta-analysis Of Observational Studies in Epidemiology
NHP Neighbourhood Policing – a model of policing based on local, named staff responsible for problem-solving in discrete geographical areas.
NICL National Incident Category List – the categories of incident set out in NSIR
NNT/NNH Number needed to treat/harm
NSIR National Standards for Incident Recording – Home Office rules on how policing incidents should be coded.
NYCC North Yorkshire County Council.
NYP North Yorkshire Police.
OPCC Office of the Police & Crime Commissioner.
PCC Police and Crime Commissioner.
PCSO Police Community Support Officer.
PCU NHS Partnership Commissioning Unit.
PNC Police National Computer – a UK-wide system to record details of people with criminal records; vehicle ownership; identifiable stolen property.
PREM Patient Rated Experience Measure.
PSW A tag on STORM to denote Public Safety and Welfare related matters – the largest category of policing incidents.
QALY Quality-adjusted life year
RCT Randomised controlled trial
S136 Section 136 (Mental Health Act).
SNT Safer Neighbourhood Teams – the Neighbourhood Policing officers & PCSOs responsible for local problem-solving in each area.
SPA Single Point of Access.
SRCCG Scarborough & Ryedale Clinical Commissioning Group.
STORM Police command & control system, used to record the initial details of an incident and the policing response.
VoYCCG Vale of York Clinical Commissioning Group.