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Hierarchy Levels -Winter 2016
Transcript of Hierarchy Levels -Winter 2016
Winter Semester (2016)
Levels of Evidence
'Evaluating the evidence means sifting through the articles and studies you have found in order to decide which are valid and clinically useful' (Law, & MacDermid, 2008, p. 121).
When deciding on which articles to cite in your literature review paper ...how did you decide on quality of the article?
Ranking levels of evidence:
'The concept of ranking levels of evidence is based on the principle that certain study types have more rigor and these higher quality study designs provide more confidence to associated clinical decisions' (Law, & MacDermid, 2008, p. 123).
Importance of levels of evidence:
'Levels of Evidence are important as they are a quick classification of evidence quality' (Law, & MacDermid, 2008, p. 123).
There are many different evidence classification systems out there:
Below we have various example evidence classification systems and you will see their are many similarities between evidence hierarchy ranking systems.
Evidence rankings should have the same theme (i.e., moving from systematic reviews down to more individual assessments).
Lower levels of evidence have LESS control over potential sources of Bias.
Their are many different evidence classification systems. For this course however we will
stop using Polit & Beck's version
and use only
AOTA's Level of Evidence
AOTA's Levels of Evidence
The point of showing you the many other classification systems is to give you a better understanding of
how to rank the evidence you are reviewing in the articles
.... BUT for this class
MOVING FORWARD WE WIL L USE AOTA's Levels of Evidence
Please review these two videos for a nice introduction to two other kinds of evidence classification systems .
Troya, E. (2010). A Job for Superman. [Digital Photograph]. Retrieved from http://www.flickr.com/photos/eneas/6313347276/
Categorizing levels of evidence will help you manage a seemingly overwhelming task :)
Various example of the Many different types of evidence classification systems
This double-decker evidence classification system is interesting
Note: for Quiz #3 you will be held responsible for this material on the Tomlin and Borgetto article
What does this article ADD?
This model adds Qualitative Evidence into the hierarchy
Be sure to know the definition of External validity. Including terms such as:
Applicability of findings
In Qualitative Design called
Be sure to know the definition of Internal validity. Including terms such as:
Correctness of conclusion
In Qualitative Design called "Authenticity"
Good to know what the authors are pointing out here re: Internal validity versus Generalizability
Uniqueness of Qualitative Design Studies
Please know the theoretical advantages.
As well as the disadvantages.
Key Points to Remember
NOTE: The Levels of evidence are based on AOTA Evidence-Based Practice Project link
Levels of evidence
are based on AOTA Evidence-Based Practice Project link
According to the Levels of Evidence Hierarchy presented in the
Polit & Beck
textbook what type of study is delineated at a ‘Level I’ classification?
a. Systematic reviews
b. Single randomized control study (RCT)
c. Single non-randomized trial (Quasi-Experiment)
d. Expert Opinion, Case Reports
What is considered the "Best" Evidence?
What if I said: "For your literature review (Assignment #7) you were only allowed to cite Level I - evidence?
Is there a consensus about what constitutes the best or most rigorous evidence?
Systematic review of literature vs. Meta analysis-statistically combining numerical results.
RCT - randomly assign participants into experimental group & control group
Researchers goal is to
..... as it can distort the results/findings....
sampling bias /selection bias
= more likely to generate the desired result
= only white males (can you generalize?)(external validity)
= attrition bias - participants not losing weight drop out of study.
= convenience sample of volunteers (who volunteers?)(online survey?)
= sample does not represent the population (external validity)
into each group.
= adequate sample size
Response bias = reporting bias (not want to divulge answers)
= participant gives answers they feel we want
= participants (self-select) only respond to survey b/c they are motivated.
Reliability = instrument produces similar results
= one day you weigh 170lbs and next day you weigh 195lbs
Confounding bias = A third effect interferes or obscures your research "something else"
= Example of Back belts worked to prevent back strain but the 2 groups were
different in the amount of lifting they did..... how do you combat this?
2-Groups but NOT randomized....
-cohort study = 2-cohorts followed prospectively (intervention can be applied)
-case-control study = 2-groups retrospective (no intervention) who has the disease...
Good to know this:
Expert Opinion - not to be confused with "personal experience"
Expert in the field - opinion.....
Case Report - Describes an individual case eg. unique case of disease or condition
Narrative literature review - what we have started in this class. Based on subjectivity of the authors....
VERSUS systematic review -which describes the methods used in the lit. review. is more rigorous.
In Class Assignment #1
- Get back into your Literature Review Paper
- Download the Worksheet from Course Content folder for Week #9 (titled -
Summary of Study Designs of Articles Selected for Appraisal
Spend 45-minutes categorizing your articles
that you appraised in your literature review study.
- Place the corresponding number count in the table.
- What do you not put in the below table?
Pick one person in your group to show your table to the class and report on discussions your group had.
**Turn this form into Dr. Davenport
In Class Assignment #2
- Everyone come to the front of room and
select random sheet of paper to determine which side you will argue for or against
Tomlin & Borgetto's new Research Pyramid evidence model (#1-18)
OR the original Single-Hierarchy Model.(#19-36)
save your number
-Everyone goto NSU database and download:
Tomlin, G., & Borgetto, B. (2011). Research Pyramid: A new evidence-based practice model for occupational therapy.
American Journal of Occupational Therapy, 65, 189–196. doi: 10.5014/ajot.2011.000828
- Quietly read the article: 15-minutes -take notes to build your argument
- Dr. Davenport will announce the start of the ...additional 10-minutes to create an argument (build your case) for your respective side. Can work individually or in group of up to 3 people.
- Dr. Davenport will reveal the 2 people on each side that will argue their respective side. Either:
- Tomlin & Borgetto's new Research Pyramid evidence model (#1-18)
- OR the original Single-Hierarchy Model.(#19-36)
- 5minutes for the 2 people on each side to collaborate