This thesis is formed of three separate essays. The essays are empirical in nature and use the Kagera Health and Development Survey from Tanzania. The survey spans a 19-year period offering a unique opportunity to study many long-run dynamic processes of development in rural Africa. In the first essay, a version of which was co-authored with Joachim De Weerdt, we use these data to shed light on how mass internal migration changes the nature of informal risk-sharing. By quantifying how shocks and consumption co-move across linked households, our analysis shows that migrants unilaterally insure their extended family members who remain at home. This finding contradicts risk-sharing models based on reciprocity, but is consistent with assista...