ether senior resident stats talk 29 jan 2016
TRANSCRIPT
ETHER 29 Jan 2016
His Greatness,NSY
I hate stats
Medutainment
#ih8stats
ih8stats
https://www.sli.do/event/qt6qioy3/wall
Why use statistics?
But is the Truth true?
An Example
Asiana Flight 214
AmTrak
Why not ask bus drivers instead?
Type of Paper
Intervention
Drug Trial
RCT Observational
Case reportCase series
Case control
Cohort
Meta-analysisSystematic Review
Type of Paper
Intervention
Drug Trial
RCT Observational
Case reportCase series
Case control
Cohort
Meta-analysisSystematic Review
What is the question?
Why this question?
How to answer this question?
Inclusion / Exclusion
Methodology
Actual stats calculation
Conclusions and relevance
RCT - Intervention
Interim analysis
No control group.
Significant conflict of interest
COD: Fudgy terminology
Small numbers
Politics
Fame
Money
True Truth
Define a “good” journal
Industry sponsored trialBMJ 7%
NEJM 32%
CitationsIndustry sponsored > other source of funding
Reduction in Impact Factor1%15%
Reprints
Oct 2010
Nov 2009
May 2015
…half baked ……tendentious …
…ill advised …
Politics
Fame
Money
True Truth
https://www.sli.do/event/qt6qioy3/wall
What to make of negative studies?
risk
of d
eath
untreated risk of death
redu
ctio
n of
risk
of d
eath
untreated risk of death redu
ctio
n of
risk
of d
eath
untreated risk of death
A B C
redu
ctio
n of
risk
of d
eath
untreated risk of death
adverse effectsris
k of
dea
th
untreated risk of death
treatmentris
k of
dea
th
untreated risk of death
no treatment
ABC
Why ask this question?How to answer this question?
Is meta-analysis the right method to answer this question?
Meta-analysis
What’s the result?How do we know the results
valid?
Meta-analysis
G.I.G.O
Garbagedata
Garbageresult
Garbage analysis
Where How Quality
DataReproducible Robust
Meta-analysisHow do we know the results
valid?
Search databases / termsIndependent extractionPredefined data formAgreeing how to disagree
Meta-analysisHow do we know the results
valid?
Publication biasFunnel Plot
DataReproducible Robust
Problem of negative studies
“Perfect”data
Garbageresult
Garbage analysis
Observation vs intervention
Heterogeneity
Random vs fixed effect
Sensitivity Analysis
Meta-analysis
Meta-analysis
Heterogeneity - I2
Lower = less heterogeneityHigher = more heterogeneity
describes the percentage of variation across studiesthat is due to heterogeneity rather than chance
Meta-analysis
Random vs Fixed Effect
One true effect size shared by all the studies
True effect vary so each study estimates a different effect size(when significant
heterogeneityexist)
Sensitivity Analysis
Meta-analysis
Performing analysis with different assumptionsto see if result remains the same
How to apply the results?
“Perfect”data Result“Perfect”
analysis
Meta-analysis
Take home messages
Medutainment is realand here to stay.
Paper critique is about logic.
If you are worried about Exit Paper critique,you are probably suffer from imposter syndrome.
PerfectExcellence
Good enough
https://www.sli.do/event/qt6qioy3/infographic