What is the criteria for Solid, Lean, and Swing?
60%+
55% to 60%
45% to 55%
40% to 45%
40%-
??
Based on statistics from 2000-2010 Congressional races I use the following divisions:
PVI 0 or 1 tossup. Statistically the parties are equally likely to win in an even national environment.
PVI 2 to 5 competitive. Statistically the majority party will win about 75% of the time.
PVI 6+ uncompetitive. Statistically the majority party will win over 90% of the time.
Translating this to electoral margins in the two party vote one needs to adjust for the national average, since it can add or subtract a few percent. Then using your labels I would say
Swing: up to 51.5%
Lean: 51.5% to 55.5%
Solid: Over 55.5% (note that this is an 11 point margin or better)
