Through The Ages-Part II-Rules of Analysis and Flow of a Game

Here are some of the basic rules I'm adopting for analysis of TtA:

• Number Players: 4
• Expansions: None (base game only)
• Number of Rounds in Game: 20
• Age A  = 1
• Age I   = 7
• Age II  = 6
• Age III = 4
• Age IV = 2

Number of Players
The general analysis doesn't change with much with the number of players, as discussed below.  The game plays differently, however, as there is less time for card to go from back of the card row to the front.  However, there must be some point of comparison, so I choose a full game.
Expansions
At the moment I'm just focusing on the base game.  There are 3 unofficial 'expansions' for TtA, but the base game alone has loads of material to cover.  If enough people are interested I may revisit some of the expansions and discuss them in separate articles.
Number of Rounds
Now here is an important item, and the first point to make about analysis!  Through The Ages has a variable end condition.  When civil cards run out of play, the game will last one more round, and the game ends.  Sin
ce culture accumulates from every player's turn, the number of rounds the game lasts will impact score.

Every turn, if a player does not select a card, a certain number of cards are discarded from play:

• 2-player games= 3 cards removed
• 3-player games=2 cards removed
• 4-player games=1 card removed

The theoretically longest games would occur if each player only took the cards which would be removed during their turn.  There are 185 civil cards in the decks, but 10 of them must be in play on turn 1, leaving 175 cards available for choosing before the decks run out.  The following table lists the maximum theoretical length a game should last is as follows:

# Players	Max Length
2	31
3	31
4	45

Reality Check

Theory is all well and good, but reality differs widely.  After reviewing over 200 completed games (chosen randomly) from BoardGame Online.  Except for a few "special games", most games lasted from 18 to 24 rounds.  A basic breakdown of the games is found in the graph below:

Game Length by Number of Players

The 2-player and 4-player games appear to end in either 20 or 21 rounds.  The shortest games are around 18 rounds, while the longest games may stretch out to 26 rounds.

One point of interest is the 3-player games, which end one or two rounds sooner than the other games.
Age Breakdown
The availability of a card will depend on its "Age".  Ancient cards are available on Turn 1.  Age I cards will be available on Turn 2.  Age II will be available after all Age I are in play, and similarly for Age III.  From studying several games in detail, I've deduced the average length of the Ages as follows (4-player game only):

Age	Length
A	1
I	7
II	6
III	4
IV	2

These numbers are critical for analyzing other elements for comparison purposes in later articles.
Analysis
In general, players of TtA should expect an average of 20 or 21 rounds if playing 2-player or 4-player games.  In 3-player games, this numbers should be expected as 19.  To keep the numbers simple, for the sake of our analysis, 20 Rounds is a reasonable estimate.
How to Use This Information
Since a game lasts 20 rounds, this means each player should plan on having 20 rounds.  The number of actions will differ depending on governments and other factors, but at a minimum each player will have the option of 80 actions to decide the fate of their culture.

Allocating these 80 actions will be the topic of discussion for future articles.

*Edited per the corrections identified by "Dang". --Good Job, Dang!