Which type of research study provides the best evidence in an evidence report?

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Background and Objectives
Study Design and Setting
Cited by (0)
Types and levels of evidence
Systematic reviews and meta-analyses
Clinical trials
Other study types
Best evidence for different types of clinical questions
Critical appraisal is important
Which type of research study provides the best evidence in an evidence report quizlet?
What form of research provides the best evidence?
What is the best source of evidence?
Which level of research evidence is the strongest?

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Abstract

Background and Objectives

There is considerable actual and potential waste in research. The aim of this article is to describe how using an evidence-based research approach before conducting a study helps to ensure that the new study truly adds value.

Study Design and Setting

Evidence-based research is the use of prior research in a systematic and transparent way to inform a new study so that it is answering questions that matter in a valid, efficient, and accessible manner. In this second article of the evidence-based research series, we describe how to apply an evidence-based research approach before starting a new study.

Results

Before a new study is performed, researchers need to provide a solid justification for it using the available scientific knowledge as well as the perspectives of end users. The key method for both is to conduct a systematic review of earlier relevant studies.

Conclusion

Describing the ideal process illuminates the challenges and opportunities offered through the suggested evidence-based research approach. A systematic and transparent approach is needed to provide justification for and to optimally design a relevant and necessary new study.

Keywords

Evidence-based research

Systematic review

Evidence synthesis

Research ethics

Medical ethics

Clinical health research

Clinical trials

Cited by (0)

Using the best research evidence is important. However, sometimes the current evidence is inconclusive, or of a low quality.

Types and levels of evidence

To inform your clinical practice, it’s best to look for the highest level of evidence available. A pyramid is often used to represent the hierarchy of evidence, with the higher quality evidence at the top.

Best evidence includes empirical evidence from randomized controlled trials; evidence from other scientific methods such as descriptive and qualitative research; as well as use of information from case reports, scientific principles, and expert opinion.

Source: Patient Safety and Quality: An Evidence-Based Handbook for Nurses. Chapter 7.

For example, the following evidence pyramid provides a hierarchy of research and study types:

The levels of evidence (highest to lowest) are:

Systematic reviews and meta-analyses
Evidence summaries and guidelines
Randomised controlled trials
Cohort studies, case control studies, case series and case reports
Background information, expert opinions and editorials.

Systematic reviews and meta-analyses

Systematic reviews aim to identify, evaluate and summarise the findings of all relevant individual studies, thereby making the available evidence more accessible to decision-makers. When appropriate, combining the results of several studies gives a more reliable and precise estimate of an intervention’s effectiveness than one study alone.

Source: Systematic Reviews: CRD's guidance for undertaking reviews in health care.

Dr Benjamin Spock’s advice on babies’ sleeping position was disproved according to the evidence from studies and a systematic review. A systematic review published in 2005 concluded that:

Advice to put infants to sleep on the front for nearly a half century was contrary to evidence available from 1970 that this was likely to be harmful. Systematic review of preventable risk factors for SIDS from 1970 would have led to earlier recognition of the risks of sleeping on the front and might have prevented over 10 000 infant deaths in the UK and at least 50 000 in Europe, the USA, and Australasia.

Source: Infant sleeping position and the sudden infant death syndrome.

Meta-analysis involves the statistical analysis of results from the individual studies included in a systematic review. The article What is meta-analysis? provides an overview of this research process and recognises that "the strength of conclusions from meta-analysis largely depends on the quality of the data available for synthesis. This reflects the quality of individual studies and the systematic review".

Guidelines

Clinical guidelines are designed to support the decision-making process in patient care based on systematic reviews of clinical evidence, the main source for evidence-based care.

Clinical guidelines and trials guideFind clinical guidelines and trials in the health sciences.

Clinical trials

Clinical trials are particularly important for determining the effectiveness of interventions or therapies. The article Explaining the importance of clinical trials describes the use of randomised controlled trials.

The use of the drug thalidomide, a sleeping pill also utilised to relieve morning sickness, is an example of why it’s important to test new treatments.

James Lind’s prospective controlled trial for the treatment of scurvy in 1747 provides one of the earliest accounts of a clinical trial.

Other study types

It is not always feasible or ethical to conduct a clinical trial. Other study types can be used when ethical considerations are a factor, such as a cohort study. This was research method was first adopted by Doll and Hill in what’s known as the British Doctors Study.

Smoking had always been seen as a benign activity until researchers began to question this proposition in light of observations of smokers. In the UK, Richard Doll and Bradford Hill performed a case-controlled study in 1950 called Smoking and carcinoma of the lung: preliminary report. This was followed by the British Doctors Study, a cohort study which tracked UK doctors for 50 years. This research proved the link between smoking and cancer.

Best evidence for different types of clinical questions

When searching for evidence, the type of clinical question helps determine the study type to look for. The table below provides a guide to finding the best evidence for your clinical question.

Type of clinical question	Study types
Therapy/Treatment (Effectiveness of interventions)	Randomised controlled trial (RCT) Example: A controlled trial of Erenumab for episodic migraine
Prevention (Effectiveness of preventive measures)	RCT, Cohort, Case control, Case series Examples: Effect of a home-based exercise program on subsequent falls among community-dwelling high-risk older adults after a fall: A randomized clinical trial Cohort profile: The Childhood Asthma Prevention Study (CAPS).
Diagnosis (Validity and reliability of diagnostic test for identifying disease)	Prospective, blind controlled trial comparison to gold standard Example: Clinical diagnostic performance evaluation of five immunoassays for antibodies to SARS-CoV-2 diagnosis in a real-life routine care setting
Prognosis (Likely course or outcome of disease)	Cohort, Case control, Case series Examples: The prognosis and oncological predictor of urachal carcinoma of the bladder: A large scale multicenter cohort study analyzed 203 patients with long term follow-up Incidence, prevalence, natural course and prognosis of patellofemoral osteoarthritis: the Cohort Hip and Cohort Knee study The correlation between feeding intolerance and poor prognosis of patients with severe neurological conditions: a case-control study
Aetiology/Harm (Cause of disease)	RCT, Cohort, Case control, Case series Example: Five-year follow-up of harms and benefits of behavioral infant sleep intervention: randomized trial
Meaning (Patient experience)	Qualitative study Read the article Choosing a qualitative research approach
Cost analysis (Comparing costs and health outcomes of interventions)	Economic analysis Example: Cost-analysis of opportunistic influenza vaccination in general medical inpatients

For all types of clinical questions, a systematic review or meta-analysis may provide the best evidence.

Examples:

The association between the Mediterranean dietary pattern and cognitive health: A Systematic review
The risk of COVID-19 related hospitalisation, intensive care unit admission and mortality in people with underlying asthma or COPD: A systematic review and meta-analysis.

Read the introduction to the 2011 Oxford Centre for Evidence-Based Medicine’s levels of evidence to answer this question:

Critical appraisal is important

It’s essential to evaluate the quality of evidence. There are a number of critical appraisal tools or checklists for this, including the Critical Appraisal Skills Programme (CASP) checklists.

These Critical appraisal videos (YouTube 21m14s) examine 10 principles that can be applied when critically appraising literature.

Bias

An understanding of the role of bias in research is also fundamental in determining the quality of evidence. Smith and Noble state that:

Understanding research bias is important for several reasons: first, bias exists in all research, across research designs and is difficult to eliminate; second, bias can occur at each stage of the research process; third, bias impacts on the validity and reliability of study findings and misinterpretation of data can have important consequences for practice.

Source: Bias in research.

There are many biases that can affect health research, as mapped in the Catalogue of bias.

Health researchLearn about advanced health research techniques.

Which type of research study provides the best evidence in an evidence report quizlet?

Randomized controlled trials provide the strongest evidence for demonstrating cause and effect.

What form of research provides the best evidence?

Systematic Reviews and Meta Analyses Well done systematic reviews, with or without an included meta-analysis, are generally considered to provide the best evidence for all question types as they are based on the findings of multiple studies that were identified in comprehensive, systematic literature searches.

What is the best source of evidence?

Peer-reviewed journal articles based on research studies are your best sources of evidence-based information.

Which level of research evidence is the strongest?

The systematic review or meta-analysis of randomized controlled trials (RCTs) and evidence-based practice guidelines are considered to be the strongest level of evidence on which to guide practice decisions.