I believe the economic might is measured by how much you are making in total (that is to say before you pay for production/maintenance). So you could be making 500++ bc per turn and be the worst in economy or you could be making -500 bc per turn and be the best economy.

There is also a tab for treasury that lets you know how much money each civilization has saved in their tresury. Is this what you are looking for?

Depends on what stage you are at in the game. A few players have been able to make over one MILLION bc/turn later on.

The economic might rating is probably telling you the truth -- you are slightly behind the AI average in revenue.

Yes! The idea behind the ratings is to get an idea how well you are doing compared to the other factions. Everything is relative in this game. While you think 500bc profit is a lot (for instance compared to your economic status at the beginning of the game), there are many situations where this same economic status is very bad. For instance if your enemy is making 5000 bc / turn, which is perfectly possible under certain circumstances, depending on map size, resources etc.

I don't know how the score is calculated actually, but I imagine it goes something like this:

We have 2 players, you and one AI
You have an impressive '100' in absolute military score (a number indicating your absolute might, calculated from number of ships, total attack points, hitpoints etc.)
The AI has '200' in absolute military score

Instead of you now have to compare your absolute score to all the other players in the game to get an indication how well you are doing, it would be nice to get a global indication of how well you are doing COMPARED to all the other players.

A good indication of how things are going in the galaxy is to take the AVERAGE of military might across all players.

Average military might: (100 + 200) / 2 = 150.

So you scoring 100 compared to the average of 150 already indicates your military might is below average. To get one number of your-might-compared-to-others you could calculate what PERCENTAGE your score is of the average. In this case:

Percentage mil. might of average: (100 / 150) * 100 = 67

So independent of how many players there are or whether absolute mil. might is in the hundreds, thousands or millions, you always have a relatively clear indication of how well you are doing. Note that in this case the enemies might is rated at 133. If your military stays the same, but the AI's get stronger, your military rating will drop, giving you a cue that you should improve your military. If you have a score of 100, you're average in military (notice that you get hints in the game to try to achieve a score of 100 or more).

Obviously, this example for military score works also for economy and the other variables.

I will live by it I think  

Alright, your explaination does makes sense. Tks alot. =]

Does anyone have any other theories?