The problem with calculating a "velocity" for your team when using #Scrum in combination with Fibonacci-based storypoint sizes, is that completing 3 backlog items of size 8 is not the same as completing 8 backlog items of size 3, or 24 backlog items of size 1. The difference in effort and uncertainty makes such numbers a useless basis for comparison and prediction.
And following the example of XKCD in https://xkcd.com/2295/ : adding garbage numbers together leads to worse garbage numbers.
