Research Methods, Critical Appraisal, Audit & Service Evaluation

Research Methods, Critical Appraisal, Audit & Service Evaluation

The Future Midwife standards require midwives to identify, critically analyse and interpret research evidence and data (1.4), to use and share research findings to inform practice and support women's decisions (1.5), to act safely when good-quality evidence is absent (5.7), and to understand the importance of research and scholarship (5.16) and midwives' contribution through research, audit and service evaluation (5.17).

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Research, Audit and Service Evaluation

These three activities are often confused. The Health Research Authority's decision tool helps to classify a project:

The audit cycle is: choose a topic and standard, measure current practice, compare with the standard, implement change, and re-audit to close the loop (see the previous section).

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Research Designs and the Hierarchy of Evidence

Quantitative Research

Quantitative research measures outcomes numerically. In broad order of strength for questions about treatment effects:

1. Systematic reviews and meta-analyses of randomised controlled trials (for example, Cochrane reviews).
2. Randomised controlled trials (RCTs): participants are randomly allocated to an intervention or a comparison, which balances known and unknown confounders.
3. Cohort studies: follow groups with and without an exposure over time (for example, Birthplace in England).
4. Case-control studies: compare people with an outcome to those without, looking back at exposures; useful for rare outcomes.
5. Cross-sectional surveys, case series and case reports.
6. Expert opinion.

Qualitative Research

Qualitative research explores experiences, beliefs and meanings, using interviews, focus groups or observation. Approaches include phenomenology (lived experience), grounded theory (developing theory from data) and ethnography (studying cultures). It is essential in maternity care, for example to understand why women from some groups find services hard to access.

Mixed Methods

Combines quantitative and qualitative approaches to answer complex questions.

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Asking Questions and Appraising Evidence

PICO frames a clinical question:

• Population (for example, low-risk nulliparous women)
• Intervention (for example, midwife-led continuity of carer)
• Comparison (for example, other models of care)
• Outcome (for example, spontaneous vaginal birth)

Critical appraisal judges whether a study is valid, what the results show and whether they apply to local practice. Checklists such as the Critical Appraisal Skills Programme (CASP) tools guide this process. Key concepts include:

• Bias: systematic error. Types include selection bias, performance bias (when participants or staff know the allocation), detection bias and attrition bias (when people drop out unevenly).
• Confounding: a third factor linked to both exposure and outcome (for example, deprivation affecting both smoking and low birth weight).
• Blinding and intention-to-treat analysis (analysing participants in the groups to which they were randomised) reduce bias in trials.
• Certainty of evidence: systematic reviews often use GRADE to rate certainty as high, moderate, low or very low.

Interpreting Results

• Relative risk (RR): the risk in the intervention group divided by the risk in the comparison group. An RR of 1 means no difference; below 1 means a lower risk; above 1 means a higher risk.
• 95% confidence interval (CI): the range within which the true effect is likely to lie. If the CI for an RR crosses 1, the result is not statistically significant.
• P value: a p value below 0.05 is conventionally taken as statistically significant, but statistical significance does not always mean clinical importance.
• Absolute risk reduction (ARR): the difference in risk between groups.
• Number needed to treat (NNT) = 1 / ARR. For example, if an intervention lowers an outcome from 10% to 6%, the ARR is 4% (0.04), and the NNT is 25.

Worked example: the 2024 Cochrane review of midwife-led continuity reported caesarean birth with an RR of 0.91 (about 16% falling to 15%), with moderate certainty. This means a small relative reduction, and the midwife can explain it to women in absolute terms: about one fewer caesarean for every 100 women.

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Research Ethics

Ethical research respects participants' autonomy, avoids harm and treats people fairly. Key principles include voluntary informed consent, the right to withdraw without affecting care, confidentiality and data protection, independent ethical review, and following Good Clinical Practice and the Declaration of Helsinki. Pregnant women and babies were historically excluded from many trials, which is why evidence on medicines in pregnancy is often limited.

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Data and Reports that Inform Practice

Midwives use local, national and international data to understand risk and improve care:

• MBRRACE-UK: confidential enquiries into maternal deaths and perinatal mortality.
• National Maternity and Perinatal Audit (NMPA): compares care and outcomes between maternity services.
• Maternity Services Data Set (MSDS): national data collected from maternity records in England.
• NHS Resolution and MNSI reports: learning from claims and investigations.
• NICE guidelines and RCOG Green-top Guidelines: systematic summaries of evidence.

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Acting Safely When Evidence Is Limited

Many maternity decisions lack strong evidence, for example the best timing of birth in some conditions or the safety of some medicines when breastfeeding. Midwives act safely by:

• Using the best available evidence, including national guidelines, consensus statements and expert advice.
• Explaining uncertainty honestly to the woman, so she can make an informed decision based on her values.
• Seeking senior and multidisciplinary input and following local guidelines.
• Documenting the information shared, the decision made and the reasons.
• Reporting outcomes, so that experience adds to the evidence base.

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Midwives' Contribution to the Knowledge Base

Midwives contribute by taking part in research as research midwives, recruiting women to trials, leading audits and service evaluations, publishing and presenting their work, and working with women and families to co-produce research priorities. Clinical academic career pathways, such as those funded by the National Institute for Health and Care Research (NIHR), allow midwives to combine practice and research.