KPI widgets added to a dashboard will give you a quick overview of performance metrics. As opposed to reports — where any data you have chosen is visualized according to measured attributes — KPI widgets display key performance indicators only as determined by your organization, hence the name.
When you configure a KPI widget to a dashboard via drag-and-drop, you will choose what specific measure you want to display and how you want them displayed. Measures are computational expressions of numerical or quantitative data. Depending on the measure you choose, you’ll be given different options for how you want the KPI displayed, either compared to a time period or simply just as an attribute.