Second derivatives is about acceleration in classical physics. The second derivative of position is the force that accelerates you, in most cases gravity.
I am sick and tired of reading about positive second derivatives as a main economic indicator. As if there was the equivalent of gravity in economics.
Case in point, the jobs report. The number of jobs lost last month was less than the month before.
The optimist reading is that there is a positive force at play, there is an inflexion point: buy!
A optimist-pessimist reading says that we are losing less jobs, but we are still losing jobs: economy is still deteriorating (but less fast than last month): hold!
A pessimist reading says: the economy was in a bad shape and is now in a worse shape with less jobs to go around: sell!
Naive optimism and greed is what got us in the mess to start with. Endemic optimism is a strength of the american economy and it is also its achilles heel. This dictat of optimism where things always go up (no cycles) is un-natural, delusional. Problem is, as Nathalie once put it, that a political figure will lose the american public if you don't make them feel like winners. I think it is time the american public grow up.