A more sensible way to present the idea is to put the turning point of the parabola at the origin of the graph and then show that 5 is somewhere on the line of super-linearly increasing schedule risk.
The article stipulates that 5 is the value that minimizes execution time.
It could have put that on the y-axis, and labeled the left “extremely rushed” and the right side “extremely careful”. Maybe that would’ve been clearer, though I really think it’s clear if are charitable and don’t assume the author has made a mistake.
