Rank (Halo Wars)
From Halopedia, the Halo wiki
The Service Record shows the players current rank, score and how many more points the player needs to rank up. The player's rank is also visible as an icon next to their gamertag when in a game lobby, post game screen and other areas. There are eight ranks available in Halo Wars. The player starts as Unranked, and then is promoted to Recruit upon completing their first Public Matchmaking game.
As a match progresses players earn a "Base Score" for which they earn points by killing enemy units and buildings; Base Score is maxed out at 4000 points. At the end of the match the base score is multiplied by the "Bonus Score," resulting in a "Total Score." Bonus score is calculated based upon several factors. To earn the bonus, the player must complete a Public Matchmaking game and not disconnect. If the player wins, they receive an additional 40%. If the player loses, they still get an additional 20%. If the player is out of the game early and wants to leave, he or she will still receive the 20% bonus. Bonus score is also affected by "Combat Efficiency", a rating of 1-5 which is based on the number of units and buildings killed in relation to the number of units and buildings lost. The maximum Bonus Score is 8.40X, making the maximum "Total Score" for a single match 33600 points.