Small multiples has been very effective in comparing multiple dimension members. It shows us a tiny chart for each member. In a glance, we can see the general contrast between members.

However, those small multiples are really small. Users may want to see a larger chart, or drill down into one of the small charts. By adding visual tooltips to the small multiples, we give users the option to enlarge the charts and see more details, thus drill down. We found that the visual tooltips complement small multiples very well.

We are going to show two examples here on adding visual tooltips to small multiples. One is based on Jim Wahl's Tableau rendering of a Washington Post's graphics. It resurfaced in Linkedin because of Tableau Zen Master Kelly Martin's recommendation.
Another is based on Tableau Ambassador Matt Chambers' recent viz.
Click the above pictures to view or download the interactive workbooks.

The main steps to add visual tooltips to the above dashboards are as follows:
1. Duplicate the main chart and name it as ToolTip. Make changes to the design for detail viewing. It may look crowded initially. After filtering by action filter, it will look fairly decent.

2.Drag a vertical container in Floating mode into a new dashboard canvas.

3.Drag the tooltip chart to the vertical container in Tiled mode and set it to Entire View.

4.Set up the action filter with appropriate dimensions on the main chart that filters the tooltip chart. Run action on Hover and Exclude all values when the hovering is cleared.
5. Some of the functions won't work until you publish it to the server. (There is a curious discrepancy between desktop and server.)  The part that won't work in desktop is when hovering over the area overlaid with the tooltip chart. But it works on the server.

Voila, that's all.

You will have a single tooltip sheet for all the small multiples. You can have as many tooltips as you wish though, even one tooltip sheet per member as shown in some of my earlier posts.

Enjoy Tableau.