Guidance

Summary of the methods used to develop this guidance

Summary of the methods used to develop this guidance

Introduction

The review and economic modelling report include full details of the methods used to select the evidence (including search strategies), assess its quality and summarise it.

The minutes of the Programme Development Group (PDG) meetings provide further detail about the Committee's interpretation of the evidence and development of the recommendations.

All supporting documents are listed in About this guidance.

Key questions

The key questions were established as part of the scope. They formed the starting point for the reviews of evidence and were used by the PDG to help develop the recommendations. The overarching questions were:

1. What types of intervention or approach are effective and cost effective in preventing domestic violence from ever happening in the first place (that is, primary prevention)?

2. What types of intervention or approach are effective and cost effective in helping all those working in health and social care to safely identify and, if appropriate, intervene to prevent domestic violence? Examples may include collaborative partnerships, advice and information-sharing protocols and specialised training, both on-the-job and pre-entry.

3. What types of intervention or approach are effective and cost effective in helping all those working in health and social care to respond to domestic violence? This may include interventions and approaches to assess and improve someone's safety, reduce the risk of harm, support their recovery and prevent a perpetrator reoffending. It may also include collaborative partnerships and advice and information-sharing protocols.

4. What types of intervention and approach are effective and cost effective in identifying and responding to children who are exposed to domestic violence in the various settings identified? (That is, the violence is not perpetrated on them directly but they witness or experience it.) Interventions could include collaborative partnerships and advice and information-sharing protocols.

5. What are the most effective and cost-effective types of partnership and partnership approaches for assessing and responding to domestic violence?

These questions were made more specific for the evidence review.

Reviewing the evidence

Effectiveness reviews

One review of effectiveness was conducted.

Identifying the evidence

A number of databases were searched in May 2012 for randomised controlled trials (RCT), case-control studies, interrupted time series, cohort studies, cross-sectional studies, observational studies, systematic reviews and qualitative studies. See the evidence review for details of the databases searched.

A range of websites were searched manually for relevant grey literature.

In addition, the citation lists of all studies included in the review were searched and PDG members provided and discussed key literature 'virtually' with the external contractor. NICE also issued a call for evidence.

Selection criteria

Studies from countries in the Organisation for Economic Co-operation and Development (OECD) were included in the effectiveness review if they:

  • evaluated an intervention or approach to identify, prevent, reduce or respond to domestic violence and abuse between adults and young people who were, or had been, intimate partners

  • evaluated an intervention or approach to identify, prevent, reduce or respond to the abuse of older people by a family member

  • focused on healthcare, social care or specialised services that deal with domestic violence and abuse.

Studies were excluded if they:

  • focused on children who directly experienced domestic violence and abuse and perpetrators whose violence is directed at children

  • focussed on female genital mutilation, violence perpetrated against older vulnerable people by paid carers or violence in occupational settings

  • included interventions not linked to health and social care.

See the evidence review for details of the inclusion and exclusion criteria.

Quality appraisal

Included papers were assessed for methodological rigour and quality using the NICE methodology checklist, as set out in Methods for the development of NICE public health guidance. Each study was graded (++, +, −) to reflect the risk of potential bias arising from its design and execution. Studies graded (−) were excluded from the review.

Study quality

++ All or most of the checklist criteria have been fulfilled. Where they have not been fulfilled, the conclusions are very unlikely to alter.

+ Some of the checklist criteria have been fulfilled. Those criteria that have not been fulfilled, or not adequately described, are unlikely to alter the conclusions.

− Few or no checklist criteria have been fulfilled. The conclusions of the study are likely or very likely to alter.

The evidence was also assessed for its applicability to the areas (populations, settings, interventions) covered by the scope of the guidance. Each evidence statement concludes with a statement of applicability (directly applicable, partially applicable, not applicable).

Summarising the evidence and making evidence statements

The review data were summarised in evidence tables (see the evidence review).

The findings from the review and expert reports were synthesised and used as the basis for a number of evidence statements relating to each key question. The evidence statements were prepared by external contractors. The statements reflect their judgement of the strength (quality, quantity and consistency) of evidence and its applicability to the populations and settings in the scope.

Cost effectiveness

There was a systematic review of economic evaluations and an economic modelling exercise.

Review of economic evaluations

A search was undertaken using a search strategy developed by the review team. Studies were included if they focused on:

  • full economic evaluations of relevant types of intervention

  • high quality costing studies relevant to the UK.

Studies were categorised according to study type, methodological rigour and quality.

Economic modelling

A number of assumptions were made that could underestimate or overestimate the cost effectiveness of the interventions (see review modelling report for further details).

Economic models were constructed to incorporate data from the reviews of effectiveness and cost effectiveness. The results are reported in: Economic analysis of interventions to reduce the incidence and harm of domestic violence and abuse.

Fieldwork

Fieldwork was carried out to evaluate how relevant and useful NICE's recommendations are for practitioners and how feasible it would be to put them into practice.

It was conducted with commissioners and practitioners, including directors of public health and mental health and substance misuse services who are involved in domestic violence and abuse services. They included: commissioners, primary and secondary health care professionals, police officers, public health specialists, specialist domestic violence staff and other representatives from local authorities and voluntary sector groups.

The fieldwork comprised:

  • 10 focus groups and 20 in-depth interviews carried out in Birmingham, Bristol, Liverpool and London by Word of Mouth.

The 10 focus groups and 20 in-depth interviews were commissioned to ensure there was ample geographical coverage. The main issues arising are set out in section 9 fieldwork findings. Or see Field testing NICE guidance on domestic violence and abuse: how social care, health services and those they work with can identify, prevent, and reduce domestic violence.

How the PDG formulated the recommendations

At its meetings in 2012/3 the Programme Development Group (PDG) considered the evidence, expert reports and cost effectiveness to determine:

  • whether there was sufficient evidence (in terms of strength and applicability) to form a judgement

  • where relevant, whether (on balance) the evidence demonstrates that the intervention or programme/activity can be effective or is inconclusive

  • where relevant, the typical size of effect (where there is one)

  • whether the evidence is applicable to the target groups and context covered by the guidance.

The PDG developed recommendations through informal consensus, based on the following criteria:

  • Strength (type, quality, quantity and consistency) of the evidence.

  • The applicability of the evidence to the populations/settings referred to in the scope.

  • Effect size and potential impact on the target population's health.

  • Impact on inequalities in health between different groups of the population.

  • Equality and diversity legislation.

  • Ethical issues and social value judgements.

  • Cost effectiveness (for the NHS and other public sector organisations).

  • Balance of harms and benefits.

  • Ease of implementation and any anticipated changes in practice.

Where evidence was lacking, the PDG also considered whether a recommendation should only be implemented as part of a research programme.

Where possible, recommendations were linked to an evidence statement(s) (see the evidence section for details). Where a recommendation was inferred from the evidence, this was indicated by the reference 'IDE' (inference derived from the evidence).