Transcript SUSSER’S CAUSAL CRITERIA Nigel Paneth CAUSAL CRITERIA COMPARED SURGEON GENERAL SUSSER BRADFORD-HILL ASSOCIATION DIRECTION DOSE RESPONSE* EXPERIMENT TIME ORDER STRENGTH CONSISTENCY TIME ORDER STRENGTH CONSISTENCY TIME ORDER** STRENGTH CONSISTENCY SPECIFICITY SPECIFICITY SPECIFICITY COHERENCE COHERENCE PREDICTIVE PERFORMANCE COHERENCE*** *Included under strength in other criteria.

SUSSER’S CAUSAL CRITERIA
Nigel Paneth
CAUSAL CRITERIA COMPARED
SURGEON GENERAL
SUSSER
BRADFORD-HILL
ASSOCIATION
DIRECTION
DOSE RESPONSE*
EXPERIMENT
TIME ORDER
STRENGTH
CONSISTENCY
TIME ORDER
STRENGTH
CONSISTENCY
TIME ORDER**
STRENGTH
CONSISTENCY
SPECIFICITY
SPECIFICITY
SPECIFICITY
COHERENCE
COHERENCE
PREDICTIVE
PERFORMANCE
COHERENCE***
*Included under strength in other criteria. ** Temporality in
Bradford-Hill. *** Biological plausibility in Bradford-Hill
2. This means we must first make sure the study or
studies we examine are sound, i.e. unbiased. It
makes no sense to apply causal criteria to
studies which are badly flawed. Causal criteria
try to address the possibility of confounding
more than they do bias. They assume that the
data are in fact correct, i.e. unbiased.
3. At the level of the individual study, consistency
does not usually apply.
4. Best use of causal criteria is to assess groups
of studies. Meta-analysis usually summarizes
odds ratios, thus assessing strength, and also
formally excludes problematic (i.e. potentially
biased) studies.
CAUSAL CRITERIA AS PER
M W SUSSER
(Am J Epid 1991;133:635-648)
Three absolute requirements:
Association. The exposure and outcome
are associated more commonly than
would be expected by chance.
Time order. The exposure can be shown
to precede the outcome
Direction. A change in the outcome is a
consequence of change in exposure. (Not
the same as directionality in a study).
To best determine whether the
above criteria are met, we then look
at five additional criteria, defined
slightly differently by Susser
1.
2.
3.
4.
5.
Strength (same meaning in Susser)
Specificity
Consistency
Predictive performance
Coherence
2. SPECIFICITY
When we ask if relationships are
specific, we can mean either
a. Specificity of effect
b. Specificity of cause
3. CONSISTENCY
Susser defines consistency as "persistence
of the association upon repeated testing"
How is this persistence asssessed?
a. survivability
The association persists even with the
most rigorous study designs and analysis
b. reliability
The association persists in many diverse
study settings
4. PREDICTIVE PERFORMANCE
The association observed can predict a
previously unknown observation
5. COHERENCE
a. theoretical
Compatible with pre-existing theory
b. factual
Compatible with pre-existing knowledge
1. biologic
Compatible with current biological knowledge
from other species or other levels of
organization (e.g. cellular in humans)
2. statistical
Compatible with a reasonable statistical model
of the relationship of cause to effect
(e.g. dose-response)