Rank progression (Rookie to Ace)
Solving cases promotes the detective up ACME's ranks, with the toughest assignments — including Carmen — reserved for the top.
Success in the games is tracked as a career. The player starts as a Rookie detective and is promoted by solving cases, climbing through ACME's ranks until reaching the top. In the original 1985 game there are five levels in all, ending at Ace Detective.
Rank is more than a score. The harder, longer cases — and ultimately the case that names Carmen Sandiego herself — are only assigned to detectives who have already proven themselves. A Rookie chases the easier henchmen; an Ace is trusted with the leader of V.I.L.E.
Later titles
Subsequent games kept the promotion idea but expanded the ladder. Where in the U.S.A., for example, runs through a much longer series of titles — from Gumshoe and Junior Investigator up through Detective, Master Detective, and Super Sleuth — before a detective is considered the best in the agency. In every version the principle is the same: cases get harder as you rise, and the final promotion is earned by bringing in Carmen.