As a data analyst and creator of countless visualizations, I always get asked by curious users “what happened there?”. Whether be it a spike in traffic to the website or a sudden drop in new sign-ups. Providing the ability to break down the aggregated data using filters or drill through can help the viewers self-discovered the reasons behind the anomalies. And help free you up from ad-hoc requests.
Best Practices
The key is to make sure the underlying data contains enough and relevant data points to help users further explore the data through self-service discovery and exploration. Appropriate ordering and naming of columns can go a long way here. Most modern data visualization tools come with the ability to filter and drill through the data on the fly. Make sure to add interactivity to your visualizations or dashboards and inform non-technical viewers on how to use them.
Screenshots
Using one of the many drill through options in Metabase to see the records that compose the value.