Roll Call and CQ Weekly use ratings assigned by the Rothenberg Political Report, which are defined as follows:
SAFE: As of today, the party indicated is all but certain to win the seat.
FAVORED: One candidate has a substantial advantage, but an upset is still possible.
LEAN: The party indicated has the edge, but the outcome is less certain than for races rated as favored.
TILT: The outcome is effectively regarded as a tossup for each of these highly competitive seats, although the party indicated has a slight edge.
TOSSUP: Neither party has an edge in these contests.