That's relative, isn't it? Below average is effectively negative for most purposes. Contrary, the Root Mean Square of a sinusoid AC supply can't go negative, fo

That's relative, isn't it? Below average is effectively negative for most purposes. Contrary, the Root Mean Square of a sinusoid AC supply can't go negative, for example. Economy (or socio...) is maybe not that simple, but still based on a balance between giving and receiving. What's interesting then is the average of the slope: zero for AC pretty much by definition. While stability is important, growth is too, economically speaking, so the derivative would need to be normalized under an average, so we are back to square one. That's to say, of course people can be on the decline.