September 21st, 2023
Hey, this is Ivan, a developer here at Datawrapper. This week I made a chart to help me make a financial decision.
Winter hasn’t even started and the ongoing energy crisis is already making our lives more expensive. That is why governments are coming up with different ways to help with the financial burden on their citizens. In Germany, the federal government issued a (very cheap) special ticket for public transport in the months of June, July, and August of this year. It was meant to reduce the cost of living and simultaneously tackle the climate crisis by encouraging people to use trains, trams, and buses instead of their own cars. It cost 9 euros per month and allowed unlimited travel within the country by public transport (with the exception of high-speed trains).
Sadly, the popular ticket (some 52 million were sold) is no longer available and so far no reduced price alternative has been offered nationally, although further ideas are currently being explored. But starting from October, the local government in Berlin, where I live, is introducing its own version of a reduced price monthly ticket. It will cost €29 and will allow unlimited travel within zones A and B, which cover most of the city. It’s a big reduction from the original €86 but not as significant as the €9.
So I’m faced with a dilemma: Should I buy this ticket? To help me answer this question, I made a chart to show how much I’ve spent on public transport in the past:
At first sight there is no overwhelming conclusion on whether I should buy the 29 euro ticket. In most months I spent less than €29, but there are others when I spent a lot more. There are also quite a few months where my spending was actually very close to €29.
Looking purely at numbers would suggest that I should not be buying the ticket, because in the past, on average, I spent less than €29 per month. But life is too complex to be explained only by numbers! The amount of money that I spend is an important factor, but it's not the only one that goes into making this decision.
There are a couple of additional positives associated with a monthly ticket that are not directly reflected in the price:
For these reasons, I decided that… *drumroll* I will buy the 29 euro ticket. It’s close to my average monthly spend and it’s so much more convenient!
To obtain this data, I downloaded transactions from my bank account filtered for the name of the BVG (Berlin's public transport company). I buy all tickets electronically using my phone so my bank has a record of all the times I bought tickets. After a bit of fiddling and cleaning up the raw data in Numbers (a spreadsheet software for Mac OS), I was able to aggregate my total transit spending per month.
To visualize the data I used a column chart. Instead of showing the total amount spent, I used the price of the 29 euro ticket as the baseline, to show for each month whether I paid less or more than this amount. To calculate this baseline, I subtracted 29 from each monthly spending. Although using a different baseline means it takes a little more time to understand this chart, I think it does well to communicate the difference from €29, which is what I set out to find out with this Weekly Chart. I also added text and range annotations to highlight different types of ticket that I bought in the past.
Working on this Weekly Chart was fun because it made me wonder why I spent more or less money on public transport in certain months. For example, looking at the high outliers in August 2021 and March 2022 made me realize that I had family and friends visiting back then, so I traveled a lot to see them and go on trips.
You may also wonder why, in the past months when I had a monthly ticket (either the normal monthly ticket or the 9 euro ticket) I sometimes still spent additional money. Some of this is already explained in the annotations but here is the full list of reasons:
Making this Weekly Chart and thinking about pros and cons of different tickets helped me make the decision to buy the 29 euro ticket. Collecting and visualizing data about oneself (this idea is also known as the "quantified self") can be useful to inform different kinds of financial and life decisions. But don't forget that you shouldn't only rely on raw data — consider your own personal situation and use your gut feeling! 🙂
That's it from me this week! I hope I inspired you to think about how you could use data visualization to help you make some decisions in life. Let me know if you have comments over at firstname.lastname@example.org or on Twitter — we'll see you next week!