I’m not sure how a term from construction and dentistry became so ubiquitous in the world of data analysis. Perhaps because when you are “drilling down” into data, you are going deeper. Drilling-down means viewing data at increasing levels of detail. (By the way, the word for viewing data at decreasing levels of detail is called “rolling-up”, a culinary term?)
You can create interactive data visualizations with applications like Tableau and Qlik Sense. Then users can “drill down” into the data. Let's say you see an overall downward trend in program participation. You might want to see if the trend holds for subgroups of participants such as women, men, or those in certain age groups. You do this by employing filters. By clicking on a checkbox for “women”, you see only the trend for women. By then clicking on a checkbox for “16-24”, you see the trend only for women in that age group. Indeed, you can create a dashboard with multiple charts, graphs, and maps and filter them all simultaneously. Check out this example of an interactive visualization on my website.
Why is drilling down important? Because it helps you to identify both strengths to build on and problems to address. An overall upward trend can hide problems in subgroups. For example, perhaps participants in a certain age group are not doing as well in the program as others. Conversely, overall negative results hide positive findings. For example, on average, the wages of participants in an employment program have gone down. But they may have increased for a subgroup who entered the program after a certain date.
Bottom line: Don’t only look at the forest. Check out groups of trees to get the whole story.
See other data tips in this series for more information on how to effectively visualize and make good use of your organization's data.