What’s the Difference Between Sketch Comedy and Improv?

First: sketch comedy is scripted, improv is not. While there are TV shows that employ some improvisation (Curb Your Enthusiasm, The Office), they are still working within the framework of a script; they know what the story is, even if the dialogue is not always set in stone. Improv, when done properly, has no idea where it’s going at the onset. The story unfolds for the actors at the same time it does for the audience, which is one reason why improv is such a wondrous art to take part in.

Second: sketch comedy is, by definition, comedy. It’s always trying to be funny. In fact there are people whose job it is to “punch up” scripts by adding or polishing jokes. The typical sitcom script will have at least 5 or 6 laugh-lines per page. A high percentage of improv is comedic, but it doesn’t have to be. While performing in a festival this year, we ended our long-form scene in a graveyard with one character talking to the tombstone of her late husband. A non-comedic end to a mostly-comedic scene, something you will rarely see in sketch comedy.

Some groups (Second City, most notably) will use improv as a basis for their sketch. They will present a show of improv for the purpose of gleaning material which can be worked up into viable sketches. It should be noted that this is not “sketch-based improv,” but “improv-derived sketch.” While the improv is used as a launching point for the sketch, it does not make the sketch improv. Confused yet?

Basically what it comes down to is this: sketch is written and rehearsed before the fact, improv is created on-the-fly. Both have their merits, but they are very different animals.