The lag is approximately six months, so we should start to see signs in the summer. Consumer confidence has fallen somewhat, but is still high in historical terms. There is a US federal budget surplus. Taxes in the US are coming down. The money supply in the US is growing.
Employment is high.
We have political stability. All of these factors point toward economic growth, not shrinkage. In addition we have some very positive macro level trends such as savings by the baby boomers, a generational wealth transfer, global economic expansion into new frontiers, and many new technology driven capabilities. No one knows this in advance, and we never are sure until well after the fact. This is a number that a lot of people either don't believe or are choosing to ignore.