The strengths of the
study include the ability to compare outcomes by the woman's planned place of birth at the start of care in labour, the high participation of midwifery units and trusts in England, the large sample size and
statistical power to detect clinically important differences in adverse perinatal outcomes, the minimisation of selection bias through achievement of a high response rate and absence of self selection bias due to non-consent, the ability to compare groups that were similar in terms of identified clinical risk (according to current clinical guidelines) and to further increase the comparability of the groups by conducting an additional analysis restricted to women with no
complicating conditions identified at the start of care in labour, and the ability to control for several important potential confounders.
As a layman, with just a smattering of climatology education, the one thing that sticks out above all else is that the subject is immensely
complicated, and involves expert knowledge of dozens of entirely different disciplines from
statistical analysis through thermodynamics to ice core
study.