I spent most of last week fighting with a model.\xa0\nBefore anyone starts googling \u201cNerdy Economist in Fashion Week Brawl\u201d, I should clarify.\xa0 I was fighting with a macroeconomic model that insisted on telling me something I didn\u2019t believe.\xa0 To be precise, it was projecting that, given the recent and projected pace of U.S. economic growth, the unemployment rate would slide to 3.0% by the end of 2025.\xa0\nThis I don\u2019t believe for reasons I\u2019ll explain.\xa0 But the changes in assumptions necessary to produce a more reasonable answer can tell us a lot about the likely path of economic growth, inflation, interest rates, corporate profits and the dollar over the next two years with significant implications for financial markets and investing.