Re: Here's looking at you (Maybe)
AFAIK they estimate temperature based on how far it is from the star and what type of star it is, and estimate size based on how much the light from the parent star is dimmed by its passing.
Obviously a planet with Venus' atmosphere would be temperate (perhaps even still too hot) in Mars' orbit, while Mars might be liveable (assuming SPF 150 and an oxygen mask) in Venus' orbit, so there are some assumptions being made.
They are really trying to identify candidates for further study. It is the news that hypes them as being Earth-like. Some of them will probably be Venus like and Mars like, and perhaps further study and better telescopes will be able to determine which is which.