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
Typically have quantitative data, are normative, observational studies and case reports
- Look for relationships between variables
- Risk Estimate
- Do not manipulate variables
- No assignment to groups
- No control
- Group assignment
- Manipulation of Variables
- CAUSE and EFFECT
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
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
How do you perform a critical appraisal?
- screen the article
- assess methodological quality
- assess the clinical relevance of results
Screening questions: Strength of Research
Was the study original? Is there a reasonable focused research question?
Strength of Research
- Examine methods and results
- Assure authors conclusions are trustworthy - limit bias, data to support conclusions, appropriate methods, appropriate analyses
- Control group
- Blinding of assessors, subjects, practitioners
- Group assignment
- Drop outs
- Sample Size
- Statistical analyses
- Baseline characteristics
Clinical Practice Guidelines
Statements that help with decisions on specific conditions. Can change practice/outcomes.
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
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
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
How to assess a systematic review
- Is the topic well defined?
- Was the search for papers thorough?
- Search strategy described
- “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?