Transcript Document

“…If we did not respect the
evidence, we would have very
little leverage in our quest for the
truth.”
Carl Sagan
Getting the Evidence:
An introduction to
Evidence-Based Public Health
Fall 2007
Erika L. Sevetson, MS
Ebling Library, UW – Madison
Session Objectives
 Learn the definition of EBPH
 Introduction to the process of EBPH
 Learn steps to finding the evidence
Definition: Evidence-based Public
Health
 “the development, implementation, and evaluation
of effective programs and policies in public health
through application of principles of scientific
reasoning, including systematic uses of data and
information systems, and appropriate use of
behavioral science theory and program planning
models”
Source: Brownson, R.C. et al, Evidence-based public health, Oxford University
Press, 2003.
Community
Needs & Values
Scientific
Evidence
Resources
EBPH
(adapted and modified from Muir Gray)
Key Differences between EBM and
EBPH
Characteristic
Evidence-Based Medicine
Evidence-Based Public
Health
Quality of evidence
Experimental studies
Observational and quasiexperimental studies
Volume of evidence
Larger
Smaller
Time from intervention
to outcome
Shorter
Longer
Professional training of
workforce
More formal, with
Less formal, no standard
certification and /or licensing certification
Decision making
Individual
Team
Why is EBPH important?
 Provides assurance that decision making is based
on scientific evidence and effective practices
 Helps ensure the retrieval of up-to-date and
reliable information about what works and doesn’t
work for a particular public health question
 Provides assurance that one’s time is being used
most efficiently and productively in reviewing the
“best of the best” information available on the
particular public health question
Why is EBPH important?
 During the past century, average life expectancy
increased by approximately 30 years in
industrialized countries
 Only about 5 years of that improvement is
attributable to preventive services and medical
care
B
u
n
Some Key Characteristics of
EBPH





Intervention approaches developed based on
the best possible scientific information
Theory and systematic planning approaches
are followed
Problem solving is multi-disciplinary
Sound evaluation principles are followed
Results are disseminated to others who need to
know and take action
Advantages to Using EBPH
 Higher likelihood of success
― A move away from decision-making that relies too
heavily on:
• History
• Anecdotes
• Pressure from policy makers




Identify common indicators
Defend/expand an existing program
Advocate for new programs
New knowledge is generated to help others
When is EBPH used?
 when it’s important to have scientific evidence to
support decision making
 when evaluating the effectiveness and cost benefits
of health programs
 when establishing new health programs
 when policies are being implemented
 when conducting literature reviews for grant
projects.
Steps in the EBPH Process
1) Formulating a clear question from a public health problem
2) Searching the literature
3) Appraising the evidence
4) Selecting the best evidence for a public health decision
5) Linking evidence with public health experience,
knowledge, practice, and the community’s values and
preferences
6) Implementing findings in public health practice and
programs
7) Evaluating results.
Source: Jenicek, Milos and Sylvie Stachenko. 2003. Evidence-based public health, community medicine, preventive care. Medical Science Monitor:
9(2): p, SR2.
Evidence-Based Public Health
Quantify the issue
Conduct
literature
review
Define the issue
Evaluate the
program or policy
Develop program
or policy options
Develop plan
Steps in Searching the Public Health
Literature
1. Determine the public health problem and define the
2.
3.
4.
5.
6.
7.
question
Select information sources
Identify key concept and terms
Conduct the search
Select documents for review
Abstract relevant information from the
documentation
Summarize and apply the literature review
Source: Adapted from Brownson. Evidence-based public
health. Oxford University Press, 2003, p. 128.
Step 1: Determine/Define the
question (Evidence types)
Type 1 Something should be done
Type 2 This should be done
Type 3 How the intervention should be done
Step 1: Determine/Define the
question
 P =Patient/Population/Problem
 I =Intervention/Item of interest
 C =Comparison
 O =Outcome
A Scenario
C – no comparison/placebo
P
You coordinate social activities for a few of the city’s
senior centers. The latest Behavioral Risk Factor
Surveillance System (BRFSS) survey showed that
seniors in your state are not participating in regular
exercise or many other health promotion behaviors.
heard that physical activities for older adults
I You’ve
can have a host of benefits, and would like to
submit a grant to begin an exercise program. You
must find literature supporting the effect of exercise
programs in reducing injuries or decreasing risk of
chronic disease in the elderly.
O
PICO
 P = inactive seniors
 I = community exercise programs
 C = no comparison
 O = reduced injuries/chronic disease
The question…
 In inactive senior populations, are formal exercise
programs effective in reducing injuries and
chronic disease associated with the aging process?
Step 2: Select information
sources
 Systematic Reviews and Meta-analyses
 Practice Guidelines
 Journal Literature
 Best Practices
Types & Sources of Evidence
 Systematic Review: critical assessment and evaluation of
research that attempts to address a focused question using
methods designed to reduce the likelihood of bias.
 Meta-Analysis: overview that incorporates a quantitative
strategy for combining the results of several studies into a
single pooled or summary estimate.
Source: R.C. Brownson et al, Evidence-Based Public Health, Oxford: Oxford
University, 2003.
Types & Sources of Evidence
 Practice Guidelines: systematically developed statements
to assist practitioner and patient decisions about
appropriate health care for specific clinical circumstances;
may be developed by government agencies, institutions, or
by the convening of expert panels.
Source: R.C. Brownson et al, Evidence-Based Public Health, Oxford: Oxford
University, 2003.
Types & Sources of Evidence
Journal literature:
Source: Guide to Research Methods: The Evidence Pyramid:
<http://servers.medlib.hscbklyn.edu/ebm/2100.htm>.
“The best is the enemy of the good”
-Voltaire
The problem of randomized trials and
parachutes….
The effectiveness of parachutes has
not been subjected to rigorous
evaluation by using randomised
controlled trials…. We think that
everyone might benefit if the most
radical protagonists of evidence
based medicine organised and
participated in a double blind,
randomised, placebo controlled,
crossover trial of the parachute.
Smith and Pell, BMJ, 2004
Types & Sources of Evidence
 Best Practices: Public health programs, interventions,
and policies that through experience have been
evaluated, shown to be successful, and have the potential
to be adapted and transformed by others working in the
same field.
—Lacks rigorous evaluation of a systematic review or
meta-analysis
—Applied across a variety of public health areas
—Vary widely in scope, methods, and quality
—Expert opinion to systematic methods
—Some are very influential
—Best Practices for Comprehensive Tobacco Control
Programs
Evidence spectrum
Weak
No evidence/
case reports
Strong
Local needs
assessment
Best Practices
Meta analysis/ Systematic
review/ Evidence-based
guidelines
Step 3: Identify key concept and
terms
 In inactive senior populations, are formal exercise
programs effective in reducing injuries and
chronic disease associated with the aging process?
Step 3: Identify key concepts and
terms
 P = inactive seniors
 I = community exercise programs
 C = no comparison
 O = reduced injuries/chronic disease
P
Seniors/senior citizens
elderly
aged
I
exercise
physical activity
recreation
program development
program evaluation
effective programs
Step 4: Searching the literature
 Best Evidence Resources
http://ebling.library.wisc.edu/EBPH
Cochrane Collaboration
PubMed
Partners in Information Access for the
Public Health Workforce
NICHSR: National Information Center on
Health Services Research & Health Care
Technology
Step 7: Summarize and apply the
literature review
 Appraising the Evidence & Evaluating the Results
― What
type of study/evidence is it?
― What are the results?
― Are the results valid?
― Were all important outcomes considered?
― Was an explicit process used to ID evidence?
― Has the guideline been subjected to peer review
and testing?
― Can the results be applied to my context?
Thank You
Erika Sevetson
[email protected]
608.262.9506
http://ebling.library.wisc.edu/EBPH