The percentage of Poor, Middle Income and Wealthy people seems to be unaffected by functions.
I have edited votertypes.csv and altered the “overridden joins” to 1, but still there seems to be no effect when some variable increases their percentage.
Have you been more successful editing these?
The overridden joins means that these groups do not follow the normal rules that affect membership of the majority of voter groups.
The game actually models every citizens individual income, in a multi-stage process.
Every citizen has an ‘innate’ income determined at birth. This places them in one of those three income groups. Then, the policies, events and situations which affect the income levels for voters (taxes, benefits etc), are then used as appropriate for the voters, depending on their membership of these ‘innate’ groups. This will probably leave them in the same group, but may push them up or down into the next one.
So something like food stamp policy will push the top few people in the poor group into middle income. The luxury taxes will push people from wealthy down towards middle income.
I hope that helps to explain it 
Thanks, that explains another question I had; whether income levels for voter groups (retired etc) had any gameplay effect.
“The game actually models every citizens individual income, in a multi-stage process.
Every citizen has an ‘innate’ income determined at birth.”
Can we jump in at any point and change the variables? If so, is it possible while retaining the ability to upload to steam?