It’s all about the delta in the economy. That is, those little bits of change that add up and have the potential to make a meaningful impact – for better or for worse.We are seeing positive delta all over the place in the U.S. economy. On the job front, the employment numbers are getting better. On the manufacturing front, inventories are being rebuilt. On the spending front, the consumer is getting a bit more venturesome.If you go to Craig’s List, you will see that the job postings are steadily on the increase. Try to find a carpenter (as I am doing right now) to fix the garden fence destroyed by the storm two weeks ago, and he is busy. But only two months ago, he called wondering if there was any work he might do to bring home a little extra income. That’s positive delta.And perhaps best of all, the state of the corporate balance sheet in the U.S. is healthy, really healthy. That, together with the astounding productivity gains they have been achieving, may encourage companies to increase capital investments. That would certainly provide more positive delta.But we all know that delta can work both ways, and we need to keep our eye on what negative delta might also be out there to offset the brightening economic picture.Here’s what comes to mind. Will China continue to be the engine of growth in this recovery? If so, then the delta force will gather strength. If not, if in fact China’s growth is peaking, we could be in for a nasty pullback.Will there be negative delta as the Federal Government stimulus program comes to an end later this year? It is hard to believe it won’t have some impact, but if the private sector has developed enough of its own momentum, maybe the two will wash each other out. That would be good news, because private sector demand is more sustainable and more profitable than Government stimulated demand.What will be the impact of the cessation of the $8000 tax credit for new home buyers at the end of this month? Most likely, it will be negative delta on home sales and home prices.What will happen when unemployment benefits start to run out? Will the delta impact be negative? Or when the census workers are no longer needed? Or what if oil prices sky rocket? For sure that will be force negative on the consumer’s pocketbook. Or if interest rates head up too soon and too fast? A few small negative bits of delta can also add up.It’s all food for thought. But for sure right now, there are more positive bits of delta than there have been for the last two years.