Under-5 Mortality rates have been decreasing across Africa for the past two decades. Contributing factors include policy changes, technology, and health investments. This study identifies sub-populations that have experienced more-than-expected change in mortality rates (either increasing or decreasing) during this time period. We train under-5 mortality predictive models on Demographic and Health Survey (DHS) datasets from the early 2000s and apply those models to data collected in more recent versions of the survey. This provides an estimate of the risk current families would have faced in the past. We then apply techniques from anomalous pattern detection to identify sub-populations that have the most divergence between their predicted and observed mortality rates; higher and lower. These detected groups are examples of successes and possible misses of the health progress observed in Africa over the course of decades. Identifying these groups through data-driven discovery may lead to a better understanding of health policies in developing countries.