#1
A slope chart connects two points in time with a line, making the direction and steepness of change the primary reading.
Lines that cross signify overtaking, making shifts in ranking visible at a glance, while parallel lines signal stability.
It is a format built for simplicity: two time periods, a small number of categories, and a clear comparison of growth, stagnation, or shifts in position.
Adding a third time period transforms it into a line chart, risking the focused comparison that makes the slope chart worth considering.