spending control chart script

[Justus Pendleton]

Yesterday I put together a script to generate a "process control chart" of spending relative to portfolio size and figured I would share it. Here's the github repo:

https://github.com/hoostus/beancount-control-chart

It has some command line options, which are hopefully self-explanatory. The idea is, for each month we look at our portfolio (for some configurable definition of that...) and our spending and see what percentage of our assets we're currently spending. This is primarily targeted at someone who is retired but maybe others would also find it interesting. Because monthly spending as a percentage of the portfolio tends to be volatile, there's a 12-month moving average with a shaded area of 1 standard deviation (of the volatility of monthly spending) wide around it. There is also an "upper control limit" which is a spending ceiling.