I have been playing GalCiv2 for some time, and thought I had a pretty good understanding of the game concepts. But I recently noticed that the Economic Capital does not fit my strategy nearly as well as I thought.
I usually do not build the Economic Capital until a bit later in the game, when I can put it on a planet with a lot of stock exchanges. I also try to make that my highest population planet. But taking a closer look at what the Econ Capital actually does, I found that the stock exchanges make no difference whatsoever.
In the manual, it states that the Econ Capital doubles the economy of a planet. We know that is not true; the in game description states that it gives a 50% economic boost. However, that 50% increase is only an increase in the base economy, not 50% increase to the overall planet economy after bonuses. That means that the Econ Capital functions exactly like 2 stock exchanges, which really is not that much of a bonus.
I found this after conquering an AI Econ Capital, and noticed that a planet with 12.0B pop, 9 stock exchanges and an Econ Capital produces exactly the same income as a planet with 12.0B pop and 11 stock exchanges. Both planets list +275% economy in their details.
This really changes my strategy regarding this super project. It seems only valuable early on, when you are only building marketplaces at 8-10% economy increase. Then an Econ Capital is worth 5 tiles. But once you are building stock exchanges, it really loses it's value. I always waited until I had stock exchanges before I built one, but this is obviously not a good strategy.
Is this the way they are supposed to work? I can see where this would be by design, as I recall a past patch in DL where the devs stated that economy was reduced in late game play to prevent astronomical income.