The Tutorial Services Dashboard is a Microsoft Power BI report that reads data that is collected via Davidson's Tutorial Services form (https://webapps.davidson.edu/academics/tutorialservices) and is stores it in one of our on-premises SQL Server databases. The report aggregates the tutorial services data to provide an overview of tutor sessions across the college and the students who attend those sessions.
The report is divided into two pages. The first page is called the "Overall Summary," and it presents data across all of the centers for an overview of tutorial services activity. The second page is called "Center Detail," and it provides a deeper analysis of a given individual center that the user selects. Users start at the Overall Summary page, and they can "drill through" to the Center Detail page.
Filtering and Slicing Data
Like all Power BI reports, the emphasis for the Tutorial Services Dashboard is on interactivity. Both pages come with a set of "slicers," which are controls that allow the user to filter ("slice") the data. In this case, the Tutorial Services Dashboard comes with two slicers: one to pick the academic term, and the other to pick a range of session dates. These slicers are synchronized across both pages, so if you change a slicer on the Center Detail page and then navigate back to the Overall Summary page, the data on both pages will be filtered appropriately.
Another way to interact with the data on the page is to click inside the tables and visualizations that are on the page. For example, to filter the Overall Summary page to only see data pertaining to the Speaking Center, click on that row in the top-right table and all of the other visualizations on the page will automatically filter down to just that center's data.
Another feature that Power BI emphasis is "drilling through," which means when you navigate from one page to another, and in the process you pass a parameter that tells the second page what data to show. In the Tutorial Services Dashboard, you can drill through from the Overall Summary page to the Center Detail page, and the parameter that gets passed is the name of the particular center that you select.
To drill through to the Center Detail page, simply right-click on the name of a center on the Overall Summary page to display the menu, then go to the Drillthrough option and select "Center Detail." This will navigate you to the page and display only the data for that center.
To navigate back to the Overall Summary page from the Center Detail page, you can either use the tabs at the bottom of the report, or you can use the Back button situated at the top-left corner of the Center Detail page.
The Tutorial Services Dashboard definitely emphasizes visualizations over text and tables, but Power BI gives you multiple ways to see the data that underlies the various tables and visualizations.
The first way is the "Show Data" option, which exists for every visualization in Power BI. To access it, simply click on a visualization or hover over it until an ellipsis icon appears in its top-right corner. Click on the icon to expose the context menu for this visualization, then click the "Show Data" option. This will cause the report to go into a mode where it displays the visualization in the top half of the screen while the bottom half displays a table of data that corresponds to the visualization.
Another technique that is available on some visualizations is to "See Records." You can get to it by right-clicking on a data series within the visualization. When you click on "See Records," the Power BI dashboard will open up a large table that shows all the underlying data filtered on the data series that you select.
"Focus Mode" is a Power BI feature that allows you to zoom in on a particular table or visualization so you can make it the center of attention and see the data better. This is especially useful for charts that are cluttered because they display information for numerous categories. The treemap visualization below is a good example, where the smaller categories of race/ethnicity are bundled in the bottom-right corner.
To turn on Focus Mode, hover over the visualization until it displays a pair of small icons in its top-right corner, then click on the left-most icon. When you do this, the chart will expand to take up the entire available width and height of the page, which should hopefully allow you to better discern the smaller categories.
"Drill down" on Time Series Data
The Tutorial Services Dashboard includes a couple of charts displaying the number of sessions that occurred during a given year, month, or day, as well as the number of distinct students who attended sessions during those periods. In Power BI, this year-month-day relationship is referred to as a "date hierarchy," and it allows us to employ a particularly useful feature called "drill down" for deeper analysis of our time series data.
Essentially, drilling down means navigating from one level of the hierarchy to another, such as going from analyzing data at the YEAR level to doing it at the MONTH level. When this feature is turned on, you can click on data points in the chart to navigate to the next level down in the hierarchy.
Drill down is not turned on by default, so you have to enable it by clicking the "down arrow" icon in the top-right corner of a particular visual. When the background of the arrow is black, this feature is enabled and you can begin drilling down into the date hierarchy.
The screenshot below shows an example of the chart after the user has drilled down from the highest level to the MONTHS for a particular year:
And then from the months down to the DAYS for a particular month:
Once you can no longer change the hierarchy by clicking on a data point, then you have reached the bottom level of the hierarchy and can go no further. At this point, you can either use the "drill up" arrow in the top-left corner of the chart to navigate back up the hierarchy, or you can disable the drill down feature and start interacting with the data at your chosen level in the hierarchy. For example, the screenshot below shows all of the sessions that took place on the 27th day of a particular month. This was done by drilling down to the DAY level of the hierarchy, then disabling drill down and selecting that day from the chart.
Another useful technique when working with the time series data is to click the "expand all" button in the top-left corner, which will take the given time period you're examining (e.g., the last 2 years) and expand it down a level so you can view two hierarchy levels in combination, such as YEAR + MONTH as shown in the screenshot below: