The chart in this app displays all articles that match the boolean query used. You can confirm what this is by opening the details tab below the chart and checking the Within, Topic and Period sections.
Each segment of the chart represents any articles that have been SmartTagged with the named sentiment.
If the chart is empty, it means that no articles exist on the dashboard that match the boolean query used in the app.
Also note that each segment of the chart represents articles that match based on any of the SmartTags attached to it. This means that if an article has been SmartTagged multiple times and with several sentiments, it will appear in multiple segments of the chart. It also means that if your boolean query targets a specific SmartTag, the chart will still represent the sentiments of all SmartTags applied to each article, not just the one in the boolean query. This is the case in the app at the top of this page; the sentiments displayed are applied to the SmartTag Automotive as well as other SmartTags applied to the same articles. In this latter case, you may want to look at only the sentiments applied to a specific SmartTag, you can do so as follows:
Let's say you have a SmartTag called Automotive and the sentiments positive, negative and neutral. First, create a What is said app for each SmartTag and sentiment combination using the following boolean queries:
Next, drag and compare all three What is said apps into one Compare app. Now set the app to Pie chart view and edit the series labels and colors as appropriate. You will now have the following app which only represents the sentiments attached to the SmartTag Automotive: