To assess the robustness of the results of our regression analysis, we performed covariate adjustment with derived propensity scores to calculate the absolute risk difference (details are provided in the Supplementary Appendix, available with the full text of this article at NEJM.org).14, 15 To calculate the adjusted absolute risk difference, we used
predictive margins and G - computation (i.e., regression - model — based outcome prediction in both exposure settings: planned in - hospital and planned out - of - hospital birth).16, 17 Finally, we conducted post hoc analyses to assess
associations between planned out - of - hospital birth and outcomes (cesarean delivery and a composite of perinatal morbidity and mortality),
which were stratified according to parity, maternal age, maternal education, and risk level.
Their research is one of the first papers published in
association with a new Department of Energy project called the Next - Generation Ecosystem Experiment (NGEE - Arctic),
which seeks to gain a
predictive understanding of the Arctic terrestrial ecosystem's feedback to climate.