Network vs Multivariate October 20 2016 Farrokh Alemi

Network. vs. Multivariate October 20, 2016 Farrokh Alemi, Ph. D.

Causal Networks 1. Association 2. Sequence 3. Counterfactual 4. Mechanism

Multivariate Model

Network Model Treatment T Mediator M Covariate C Outcome Y

Network Model with Sequence Treatment T Mediator M Outcome Y Covariate C Covariat e Treatme nt Mediator Outcom e

Every Multivariate Analysis Can Be a Network Analysis

Try It. List Your Variables?

Which is more accurate?

Multivariate Analysis Because Associations Are Concurrent

Which is more robust?

Networks Are Redundant

Networks Are Redundant Diabetes Renal Fall Survival

Jargon, Jargon Everywhere

Term Outcome Network Definition Multivariate Definition A response variable that is measured after all other variables in the study Treatment A variable that reflects manipulations undertaken to affect outcome Covariate A node, by itself, or through A variable associated with both other nodes is associated with treatment and outcome Acyclical Not possible to start from a No variable is allowed to be node, follow the directed arcs, both dependent and return to the same node. independent variable

Term Parent Children Network Definition A node that has a directed arc to another. Parents have a statistically significant association with effects independent of other variables. A node that receives a directed arc from another Descendan Any node reached by starting ts of from treatment and following treatment the arcs in the network Multivariate Definition A variable associated with another independent of other variables in the analysis and that and was measured prior to other variables A variable associated with another independent of other variables in the analysis and that and was implicitly arranged to be measured after other variables Variables that are early or late effects of treatment

Term Collider Co-parent Path Backdoor path Blocked backdoors Markov blanket (dseparation) Network Definition A common effect of two causes. A node that if stratified would make two conditionally independent nodes dependent. Two nodes that have the same child A set of nodes connected by arcs independent of the causal direction A path from outcome to treatment without following the direction of the arcs. Stratification of a non-collider node on all backdoor paths from outcome to treatment. Parents, children, and co-parents (other parents of children) of treatment. Multivariate Definition A statistically significant relationship between two variables in one subgroup but not in the population. Two covariates that collide on a third variable A set of variables pair-wise associated with each other A set of pair-wise associatedcovariates that includes treatment and outcome. Stratification that introduces no new association with treatment. Smallest set of stratified covariates that would make treatment independent from other variables.