Tracking my expenses

One new-year resolution I made last year was to understand where my money goes. From previous experiments I know that expense tracking has to be as simple as possible. My approach is to

• Use my cash card as often as possible. This automatically tracks the date and some information on the vendor.
• Use twitter to track my cash expenses. This supplements the bank account statement data.
• Edit, enrich, merge and visualise the two data sources with R. Because it is fun playing with R!

Now after more than one year of expense tracking, I can now analyse the results. The first result however, was disappointing. My cash tracking with twitter was not as complete as I thought it is. Below is a figure that displays the sum tracked with twitter divided by the sum withdrawn from my bank account for each month of 2011.

If I had tracked my cash expenses completely, the ratio would be around 100, the gray dashed line. However, it is systematically below. For September, there is an explanation: I was on holidays and did intentionally not track the expenses. But even considering that, there remain 18 percent of my cash spendings unexplained!

More analysis results will follow. If you are interested in technical aspects of the expense tracking, such as importing the tweets and bank statements, read on. However, there is no R code today, since there is no example data.