Obviously, that's a non-starter. One option is correlation analysis, a simple statistical tool available on Microsoft Excel. It measures the tendency of two sets of numbers to move up and down together. Anything above 0.5 is considered high. Correlations come with caveats, says University of Michigan economics professor George Fulton, who took a look at the results of The Detroit News analysis.troit News analysis.
Correlations say nothing about what affects what, only the strength of the coincidence.
They don't account for outside influences like changes in the U.S. economy. The smaller the sample, the less reliable the results. That means accepting that government statisticians have properly measured the auto industry over time. Basically, correlation results are only as good as the data and assumptions upon which they're based. Garbage in, garbage out.