This visualization displays recruitment rates across studies and countries using a heatmap-like grid, where each cell represents the cumulative recruitment rate (CRR) for a specific study-country pair. Users can filter the display by selecting countries and studies through multi-select dropdowns, and sort rows and columns by study code or country name in ascending or descending order. The visualization is built with Vega, using its declarative specification to define scales, signals, and data transforms, alongside jQuery for handling the selection interface and triggering updates to the Vega view.