Some strong agreements and minor disagreements here... I'll share commentary:
The education property first off has a minor bug, its PROPERTYSOURCE_DECAY in CIV4PropertyInfos.xml is a negative number rather than a positive, meaning it has a geometric progression: once you get any education in a city, it will increase by greater and greater amounts forever, giving you all the high-education buildings before you even reach the ancient era.
Turning it from -4 to 4, and removing all diffusion to/from/between terrain plots so it becomes city-only: no bad effects. Education now "hovers" over a certain value, built up by buildings or specialists (I tweaked some specialists to make education), and decaying at 4%. So say my city is producing +4 education from buildings and specialists, it will now get up to 100 education, and hover there, giving me the 100 education autobuilding. But if I want the 1000 education building, I'll need to make a lot more sciency stuff.
Great catch! Certainly goes a long ways towards explaining some of the bloat from this mechanic.
And yes, no need for plot diffusion though a trade diffusion would be nice if we could get that working without it causing the 'sloshing tank' effect we were having trouble with.
@Alberts: I presume you set this to 4 then?
But this is how it could work! Just use the decay mechanism, you don't need sources of negative education (well, maybe a couple, crime buildings especially will be candidates...yes both buildings you build that increase crime like pubs and casinos and terrorist compounds, and stuff you get from having high crime like school shootings and child labour). We could even have it depend on all the other properties! Like lead contamination from water pollution causing negative education. Low tourism causing "brain drain". High flammability making the school burn down every other turn.
I'm in agreement that we should have good interactions like these. I'm in disagreement that population wouldn't be SOME drain at least. If we think of Education RATE as an indicator of the ability for society to provide a proper focus on educating its upcoming citizens (kids and older students alike), a rate deficit being an inability to keep up with the demand and a positive value being an ability to not only keep up but stretch to improve education methods and effectiveness, then population would clearly play a major role.
The larger class sizes get the less kids get individual attention and special needs met. In general the smaller the class size the better the results. There's other factors sure. But this is a really really big one.
I would not suggest making population's drain as strong as crime but perhaps half as strong would be good at least. Decay is important too... we quickly forget as we get older what we've learned in school. And factors in society, buildings, civics, ongoing crimes in common enough frequency, etc... would surely have an effect as well. Some crimes in particular more than others. I know gangs have kept more than one kid out of school, sometimes before highschool.
Then there could also be some counteractive value to some other factors... CPS, for example (Child Support Services for those who aren't in the US) may be well and capable of creating a LOT of family problems, as much as they solve in many cases, but at least they're there to make sure grade school kids don't disappear from the education system.
Anyhow, population matters. If we were all individually tutored our whole lives we'd all be a lot more educated I'm sure.
Also, change all the negative education buildings to being active at low positive numbers, with say 1000 or so as the break-even point between losing the "bad" buildings and gaining the "good". That way you start off a game and gain all the uneducated buildings turn 1, which makes sense, and giving you less anarchy and food required for growth (great in early game) but trade penalties and all that (not all that bad). Then when you get enough stuff to have +40 or so education per turn your people finally get a basic standard of education not to have any penalties or bonuses.
Since we can't establish a set minimum yet I'd rather see population be a drain and keep the negative buildings in the negative numbers realm. If you think of a very very early tribe, kids probably were well educated to the extent of what the adults knew at quite a young age, at least enough to see it as being neither a positive nor a negative when the game starts. Another way one could see the game starting at a neutral value, the game start may reflect when humanity actually begins to think enough past pure instinct to warrant the very concept of passing information from one person to another at all.
Buildings like all those schools that are available at Compulsory Education could have their science bonuses removed entirely and replaced solely by education. If they allow you to break through the 5000 education barrier they'll give you all the science you'll need.
I really like this idea... making it clear that there is a difference. However, research should indicate exactly that... research itself. Anything that pushes the boundary of knowledge. Education is our ability to catch up the renewing generations to what has been discovered.
