July 15 (Reuters) - Federal Reserve Bank of Chicago President Charles Evans signaled Thursday that U.S. job growth has been slower than he had expected and more improvement will be needed before the central bank can start to reduce its support for the economy. “Given the more recent months of lower employment growth than I was expecting, I would say that there are still things to assess in terms of substantial further progress that needs to be met for us to make adjustments in our monetary policy stance,” Evans said in a virtual appearance at an event by the Global Interdependence Center. It will take “more than a couple of months” to sort out timing on when tapering will be appropriate, he said. (Reporting by Ann Saphir)