The long term consequences of unwanted pregnancies carried to term on mothers have not been much explored. We use data from the Wisconsin Longitudinal Study (WLS) and propose a novel approach, namely two team cross-screening, to study the possible effects of unwanted pregnancies carried to term on various aspects of mothers' later-life mental health, physical health, economic well-being and life satisfaction. Our method, unlike existing approaches to observational studies, enables the investigators to perform exploratory data analysis, confirmatory data analysis and replication in the same study. This is a valuable property when there is only a single data set available with unique strengths to perform exploratory, confirmatory and replication analysis. In two team cross-screening, the investigators split themselves into two teams and the data is split as well according to a meaningful covariate. Each team then performs exploratory data analysis on its part of the data to design an analysis plan for the other part of the data. The complete freedom of the teams in designing the analysis has the potential to generate new unanticipated hypotheses in addition to a prefixed set of hypotheses. Moreover, only the hypotheses that looked promising in the data each team explored are forwarded for analysis (thus alleviating the multiple testing problem). These advantages are demonstrated in our study of the effects of unwanted pregnancies on mothers' later life outcomes.

翻译：非意愿妊娠足月分娩对母亲长期后果的研究尚不充分。我们利用威斯康星纵向研究（WLS）数据，提出一种名为双团队交叉筛选的新方法，探究非意愿妊娠足月分娩对母亲后期心理健康、身体健康、经济福祉及生活满意度等多维度的潜在影响。与现有观察性研究方法不同，该方法使研究者能够在对同一研究中同时开展探索性数据分析、验证性数据分析与复现研究——当仅存单一数据集且其具备开展探索性、验证性与复现性分析的独特优势时，这一特性尤为宝贵。在双团队交叉筛选中，研究者分为两组，数据亦依据有意义的协变量进行分割。各团队对其负责的子数据集进行探索性数据分析，并为另一子数据集设计分析方案。团队在设计分析方案时享有完全自由，这使除预设定假设外，还可能产生新的未预期假设。此外，仅将各团队在数据探索中显现潜力的假设推进至分析阶段（从而缓解多重检验问题）。我们针对非意愿妊娠对母亲后期生活结局影响的研究，充分验证了上述优势。