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Nursing - Evidence-Based Practice

Types of Evidence

Level One: Systematic Reviews or Meta-analysis A systematic review summarizes the results of available carefully designed healthcare studies (controlled trials) and provides a high level of evidence on the effectiveness of healthcare interventions. Judgments may be made about the evidence and inform recommendations for healthcare.

Level Two: Randomized Controlled Trials

A study in which people are allocated at random (by chance alone) to receive one of several clinical interventions. One of these interventions is the standard of comparison or control.The control may be a standard practice, a placebo ("sugar pill"), or no intervention at all.

Level Three: Cohort Study

A type of medical research used to investigate the causes of disease, establishing links between risk factors and health outcomes. Cohort Studies are usually forward-looking - that is, they are "prospective" studies planned in advance and carried out over a future period of time.

Level Four: Case-Control Study

A study that compares patients who have a disease or outcome of interest (cases) with patients who do not have the disease or outcome (controls), and looks back retrospectively to compare how frequently the exposure to a risk factor is present in each group to determine the relationship between the risk factor and the disease.

Level Five: Case Reports, Case Series Case reports are considered the lowest level of evidence, but they are also the first line of evidence, because they are where new issues and ideas emerge. This is why they are towards the base of our pyramid. A good case report will be clear about the importance of the observation being reported.
Level Six: Editorials, Expert Opinion Recommendations from persons with established expertise in a specific clinical area usually based on clinical experience. Not considered a research method because critical inquiry is lacking. 
   

 

Questions and Evidence

QUESTION PRIMARY RESEARCH
 
SYNTHESIZED RESEARCH
(Secondary Sources)
DATABASE

Therapy
What is the best treatment or intervention?

Randomized Controlled Trials
Controlled Trials
Systematic Reviews

PubMed (P,S)
MedlinePlus (S)
ClinicalTrials.gov (P)
CochraneLibrary(S)
ProQuest Nursing (S)
CINAHL (S)

Prevention
How Can I prevent this problem?
Randomized Controlled Trials
Controlled Trials
Systematic Reviews PubMed (P,S)
MedlinePlus (S)
ClinicalTrials.gov (P)
CochraneLibrary(S)
ProQuest Nursing (S)
CINAHL (S)
Diagnosis/Assessment
What is the best way to asses or best diagnostic test for this patient?
Instrument Development Research   PubMed (P,S)
ClinicalTrials.gov (P)
Causation
What causes this problem?

Cohort Study
Case-Control Study
Descriptive/Qualitative Study

Systematic Reviews

PubMed (P,S)
MedlinePlus (S)
ClinicalTrials.gov (P)
CochraneLibrary(S)
ProQuest Nursing (S)
CINAHL (S)

Prognosis
What are the long term effects of this problem?

Cohort Study
Descriptive Study

Systematic Reviews PubMed (P,S)
MedlinePlus (S)
ClinicalTrials.gov (P)
CochraneLibrary(S)
ProQuest Nursing (S)
CINAHL (S)

Meaning
What is the meaning of this experience for patients?

Qualitative Study Systematic Reviews PubMed (P,S)
MedlinePlus (S)
ClinicalTrials.gov (P)
CochraneLibrary(S)
ProQuest Nursing (S)
CINAHL (S)