Vertical axis scale on CPI vs S&P Chart?

M

Marron Grosbek

Hi I love looking at your inflation chart especially as compared with the S&P 500. This is an excellent way to demonstrate how the gap between rich and poor has been growing wider constantly for at least 50 years.

That inflation chart shows a y-axis scale if you plot CPI. and a scale if you plot CPI AND S&P. Strangely, there is no y-axis if you plot S&P alone.

But the real issue is that when you plot the ratio of CPI/S&P, you get no y-axis scale no matter what you do. This is a problem for quantitative analysis. In particular, since a log scale has an arbitrary offset and an arbitrary constant multiplier, the information content of CPI/S&P on a log scale is practically zero.

On a linear scale, when you show the zero point at the bottom of the graph, you can at least calculate changes over time in percent. But to do this you need a ruler to put on your screen and a calculator to deduce the ratios (percentages). Which is a hassle.

Is there any way you can add a labeled vertical axis to the CPI vs. S&P graph?