Sorry, this is going to be a “you’re doing it wrong” comment. I will try to criticize constructively!
There are too many arbitrary assumptions. Your chosen numbers, your categorization scheme, your assumption about whether giving now or giving later is better in each scenario, your assumption that there can’t be some split between giving now and later, your failure to incorporate any interest rate into the calculations, your assumption that the now/later decision can’t influence the scenarios’ probabilities. Any of these could have decisive influence over your conclusion.
But there’s also a problem with your calculation. Your conclusion is based on the fact that you expect higher utility to result from scenarios in which you believe giving now will be better. That’s not actually an argument for deciding to give now, as it doesn’t assess whether the world will be happier as a result of the giving decision. You would need to estimate the relative impact of giving now vs. giving later under each of those scenarios, and then weight the relative impacts by the probabilities of the scenarios.
Don’t stop trying to quantify things. But remember the pitfalls. In particular, simplicity is paramount. You want to have as few “weak links” in your model as possible; i.e. moving parts that are not supported by evidence and that have significant influence on your conclusion. If it’s just one or two numbers or assumptions that are arbitrary, then the model can help you understand the implications of your uncertainty about them, and you might also be able to draw some kind of conclusion after appropriate sensitivity testing. However, if it’s 10 or 20, then you’re probably going to be led astray by spurious results.
On political reform, I’m interested in EAs’ opinions on this one.
In Australia, we have compulsory voting. If you are an eligible voter and you don’t register and show up on election day, you get a fine. Some people do submit a blank ballot paper, but very few. I know this policy is relatively uncommon among western democracies, but I strongly support it. Basically it leaves the government with less places to hide.
Compulsory voting of course reduces individual freedom. But that reduction is small, and the advantages from (probably) more inclusive government policy seem well worth it. I’ve heard it said that if this policy were implemented in the US, then the democrats would win easily. I can’t vouch for the accuracy of that, but if it’s true, then in my opinion it means that the democrats should be the ones in power.