Factories

[La Fayette]

When I started reading the archive to this forum, a few weeks ago, I found out that many tricks I had had the pleasure to discover playing civ2, such as "2 continents trading" or "repeated commodity", were quite thoroughly described by people like Xin Yu or Adam Smith.
It was like discovering brothers after a long voyage across the ocean.
That is why it was my pleasure mentioning Mark Everson's formula to help stressing that I am not in favour of factories ASAP.
There are 3 main arguments against them:
1) Low return on investment
2) Pollution
3) High opportunity cost (1 factory=200 shields=4 caravans=almost certainly more than 2000 gold or science beakers, and also 1 factory=4 transports=a great help for large scale trading overseas).
But I strongly agree with Adam Smith when he states that HD radically changes the picture, with much better return and much lower pollution.
BUILD FACTORIES, Noble Leader! (but not ASAP)!

[Hawkman]

Factories are the best investment in the game. They give you 50% faster production and the sunk costs can be amortized in just a few turns when freight units can be built.

Pollution can be easily managed with Engineers.

Factories give you the edge that quickly defeats a player without them.

All the formulas about return on investment are bogus unless they target the true return that factories produce, more units, more infrastructure. That's what this game is about.

[SandMonkey]

but on the same thought, Hawkman, if you get a great deal of pollution from a factory, you have to waste precious turns using a settler/engineer to clean it up, when they could be building roads/mines/irrigation that could further your gains.

[Hawkman]

The pollution is a downer, I'll admit, but the gains far outweigh the negatives. Two engineers can wipe out a square of pollution in one turn, so the delay is more of a nuisance than a serious problem. By this time, there is a strong road net throughout the country which helps in moving the engineers around. And many of the cities are large enough to support two or more engineers. I usually assign two engineers to each city and they pay for themselves by quickly clearing some land to bring the food supply up to where it was before the assignment, then everything after that is gravy.

If I'm concentrating on building up cities, the factories are a must. On the other hand, I've found that manufacturing plants are not needed (although they are nice to have in a war). With a factory and manufacturing plant in every city, and Hoover Dam to help out, production is so high as to make the game boring.

[La Fayette]

Edward
The math was not Barbarossa's but Mark Everson's.
I mentioned Barbarossa because he started the thread and because he demonstrated that he was thinking the same way as I was when I started developing the "3 arrows" strategy. John, I salute you.
Mark Everson must be praised, since he developed a theoretical approach of many aspects of this game. Mark, I salute you.
But,
Hawkman,
I agree with you: it is not enough telling shields. It is also precious to take into account what one does with those shields. I ran a test last night, a small simulation comparing the results of a "no factory" strategy compared with a "factories ASAP" strategy. After 25 turns, the result was in favor of "no...", but rather slightly.
I hope to be back soon with stronger evidence derived from using the "di$counted cash-flow" method (look at my thread " true value of early trade" for details).
Happy New Year!