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Differentiate between descriptive, exploratory, and experimental studies
- Descriptive - simply describing a group of individuals about a set of variables - no comparison or manipulation of variables
- Exploratory - exploring a phenomenon and how it causes two variables to relate to one another (IE trying to find correlation)
- Experimental - controlling and manipulating groups in order to eradicate extraneous variables and come to a conclusion about cause and effect
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Descriptive studies
Typically have quantitative data, are normative, observational studies and case reports
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EXPLORATORY studies
- Look for relationships between variables
- Statistics
- Correlation
- Regression
- Risk Estimate
- Do not manipulate variables
- No assignment to groups
- No control
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EXPERIMENTAL Studies
- Group assignment
- Control
- Manipulation of Variables
- CAUSE and EFFECT
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List the hierarchy of research evidence from best to worst
- -Systematic Review of Multiple RTCs
- -Randomized Controlled Trial
- -Experimental Trials without randomization or control
- -Non Experimental Studies
- -Respected Opinions
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Differences between Research hierarchy and EBP hierarchy
Levels 3 through 6 are changed to cohort studies and case control studies, case series and case reports, opinions and letters, animal research
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How do you perform a critical appraisal?
- screen the article
- assess methodological quality
- assess the clinical relevance of results
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Screening questions: Strength of Research
Was the study original? Is there a reasonable focused research question?
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Strength of Research
- Examine methods and results
- Assure authors conclusions are trustworthy - limit bias, data to support conclusions, appropriate methods, appropriate analyses
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Methodological Quality
- Control group
- Blinding of assessors, subjects, practitioners
- Group assignment
- Drop outs
- Sample Size
- Statistical analyses
- Baseline characteristics
- ETC!!!!!
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Clinical Practice Guidelines
Statements that help with decisions on specific conditions. Can change practice/outcomes.
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Goals of clinical practice guidelines
- Help individuals receive effective (and cost-effective) services
- Help identify individual needs
- Help train professionals
- Facilitate productive communication between professionals
- Facilitate quality improvement
- Indicate where more research is needed
- Uses a scientific process that is evidence-based
- Ensuring multidisciplinary approach
- Developing a guideline that is valid, objective and credible
- Each guideline recommendation is given a “strength of evidence” rating
- Indicates the amount, general quality, and clinical applicability of scientific evidence
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Five levels of Sackett
- I. Strong evidence from at least one systematic review of multiple well-designed RCTs (systematic review is more than a lit review uses explicit methods to identify, select and critically appraise relevant research)
- II. Strong evidence from at least one properly designed RCT of appropriate Size (often this is inappropriate or unethical in clinical research)
- III. Evidence from well designed trials without randomization, single group pre-post, cohort, time series or matched case controlled studies
- IV. Evidence from well-designed non-experimental studies from more than one research group
- V. Opinions of respected authorities, based on clinical evidence, descriptive studies or reports of expert committees - useful but these are biased by the experience and values of those involved and should therefore be treated cautiously, although in many areas they are currently the best available evidence
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Systematic Reviews - what are they and what do you have be careful about with them?
- Level of rigor to reviewing research evidence = rigor in production of research
- Find all relevant studies
- Synthesize the findings from individual studies in an unbiased way
- Present a balanced and impartial summary
- Available in journals and electronically
- Be careful...
- May not have been done well
- Inappropriate aggregation of studies
- Drowning of important effects
- Not always consistent with the large high quality study
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How to assess a systematic review
- Is the topic well defined?
- Intervention
- Population
- Outcome
- Was the search for papers thorough?
- Search strategy described
- Non-English
- “grey” literature covered
- Criteria for inclusion of studies
- Assessment of study quality
- Missing information
- Similar effects in the studies
- Overall findings assessed for robustness?
- Probabilities examined?
- Recommendations based firmly on quality of evidence?
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