A summary of Data Coverage is included to the right of the Differentials panel - this highlights if any of the selected locations have low data coverage, with the option to select "More Details" for a breakdown of the data available in each location.
Within the differentials panel, hovering the mouse over each location bar will also provide a summary of coverage across jobs and levels within that location.
Example tooltip, showing data coverage for the United States, for Jobs and Levels selected in the filters.
Some locations there might not be data available for a selection of jobs, levels, and industries. These locations will not be provided with a differential.