Fig. 2: Pooled equivalence between IPTW and FedECA. | Nature Communications

Fig. 2: Pooled equivalence between IPTW and FedECA.

From: FedECA: federated external control arms for causal inference with time-to-event data in distributed settings

Fig. 2

Box- and swarm-plots of the relative errors between FedECA and the pooled IPTW on four different quantities: the hazard ratio of the treatment allocation covariate estimated from a Cox model, the partial likelihood of the Cox model, the P-value associated to the hazard ratio, and the propensity scores estimated from the logistic regression. For each quantity, relative error is defined as the absolute difference between the pooled IPTW value and the FedECA value, divided by the pooled IPTW value. Each quantity was computed from n = 100 repetitions of the simulation, that is computed by running FedECA and pooled IPTW on n random draws of 1000 samples with 10 covariates. Red dotted line indicates a relative error of 0.2% between FedECA and the pooled IPTW. Boxplot and swarm-plot use the seaborn Python library’s default settings, that is: boxes are from the first to the third quartiles, the black line being the median, and whiskers extend to the lowest (resp. highest) data point still within 1.5 inter-quartile range of the lower (upper) quartile. No statistical test was used. Source data are provided as a Source Data file.

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