The right way to use Rotten Tomatoes
The film review and news site, Rotten Tomatoes, has earned a reputation with a great many folks as the go-to place for movie reviews. For those few who don't already know the site, it aggregates both critical and audience reviews into percentages of positive reviews. If the percentage of positive critical reviews is somewhere over 50%, the movie gets a tomato (for "fresh") next to it. Films with a lower percentage of positive reviews get a green, leafy icon (for "rotten"). Many folks I know check out the Rotten Tomatoes rating, and if it's low, they give the movie a pass.
This is a mistake.
The problem with this approach is that it tells you only what the critics are saying.
Many critics hold all films to the standard of the very best; they might, for example, feel it's reasonable to compare Thor: The Dark World and Casablanca. You can certainly make a case for this approach, in that all films are working in the same medium and have the same opportunities for greatness and failure.
Other critics will compare a movie to the very best of its type, pitting all the action films against that genre's greatest exemplars. Again, it's easy to make a case for this approach; after all, we'd all love for each film to hit the highest standards of its genre.
What precious few critics do is tell you whether you're likely to have a good time at a given movie if you like that sort of movie.
When you're considering going to Thor: The Dark World, the odds are good that you've seen the trailer, seen some other recent superhero movies, and already know whether you're likely to enjoy this one. Most reviews ignore this reality. What most of us want to know is whether we're likely to enjoy this Thor movie, or this Arnold movie, because we already have a strong sense of what a Thor movie is, what an Arnold flick has to offer.
Which brings us to the much better way to use Rotten Tomatoes: Check out the audience rating and its relationship to what the critics have to say.
The ideal, of course, is for both ratings to be high. If both the critics and the audiences turn in over 80% positive ratings, the odds are that the film in question is genuinely a good movie of its type.
If the critics are high on a movie and the audiences are not, odds are that the film will be arty but not a lot of fun.
The golden equation for bad movies is when the critics' rating is rotten and the audience rating is fresh. When there's a gap of at least 40 percentage points between those two and the audience rating is higher, you're likely to have a movie that delivers exactly what it promises, but no more. If you go to that movie with the right expectations, which is to say that if you go knowing full well what it's likely to be, you are going to have a good time.