I was trying to decipher and pondering what kind of tax should be and could be added in the city simulation expansion pack, and David was kind enough to give us a screenshot (shown above). And it lead me wondering, what's the real GDP per capita in game? If the data shown above is calculated base on a 20% default individual income tax, than the GDP per capita in Portland is merely about 5k, which is unreasonable low if it represent a real world income level, which is about 20k in real life in 1990 currency level. But this is based on everyone is paying tax, and its a flat tax, which both are also false in real life. Regardless the authenticity of the income level, it's more important for the mechanics to be consistent within the game, conceivably to be calculated based on Real Wage Rate level factor. However, this bares an interesting question, what's the "GDP" or more precisely the "aggregate purchasing power" of all citizens in one city?
In real life, it's obvious people don't spend every penny they earned on normal spending, but also savings and investing. But exactly what is the citizen income and expenses? If base on a 10k per capita level to calculate a 2 million population city, then the aggregate potential gross income would be near 20 billion. So does this means if you open a company and sell every possible products in game with monopoly, you would hit a hard cap of 20 billion revenue no matter what? Or do citizens "borrow money" or use "credit card" to "generate" more money to spend on and lead to a higher money demand? Or do citizens save what's not spending and "recycle" the money in saving's account (which then would become the reserve of banks)?
I believe this should be a core issue to set up a realistic economic simulation, like the income/expenditure charts of citizens, and their interaction with the financial sector. It would be great to see the citizen expenditure pie chart of how many they spend on what kind of products, and how many are from AI/player corporations, and how many are local and unseen utility and service sector businesses. Also it would be great to see the saving/borrowing level of citizens become the corner stone of financial sector for money supply/demand. Money doesn't grow on trees, but could be from a semi-realistic money creation process like in real life banking.
![Image](http://www.creditloan.com/blog/wp-content/uploads/sites/2/2012/06/paycheck.jpg)