information:filtering, structural:summarization, stylistic:style_transfer
Structure and process

Improvisational theatre often allows an interactive relationship with the audience. Improv groups frequently solicit suggestions from the audience as a source of inspiration, a way of getting the audience involved, and as a means of proving that the performance is not scripted. That charge is sometimes aimed at the masters of the art, whose performances can seem so detailed that viewers may suspect the scenes are planned.

In order for an improvised scene to be successful, the improvisers involved must work together responsively to define the parameters and action of the scene, in a process of co-creation. With each spoken word or action in the scene, an improviser makes an offer, meaning that he or she defines some element of the reality of the scene. This might include giving another character a name, identifying a relationship, location, or using mime to define the physical environment. These activities are also known as endowment. It is the responsibility of the other improvisers to accept the offers that their fellow performers make; to not do so is known as blocking, negation, or denial, which usually prevents the scene from developing. Some performers may deliberately block (or otherwise break out of character) for comedic effect—this is known as gagging —but this generally prevents the scene from advancing and is frowned upon by many improvisers. Accepting an offer is usually accompanied by adding a new offer, often building on the earlier one; this is a process improvisers refer to as Yes, and... and is considered the cornerstone of improvisational technique. Every new piece of information added helps the improvisers to refine their characters and progress the action of the scene. The Yes, and... rule, however, applies to a scene's early stage since it is in this stage that a "base (or shared) reality" is established in order to be later redefined by applying the "if (this is true), then (what else can also be true)" practice progressing the scene into comedy, as explained in the 2013 manual by the Upright Citizens Brigade members.

The unscripted nature of improv also implies no predetermined knowledge about the props that might be useful in a scene. Improv companies may have at their disposal some number of readily accessible props that can be called upon at a moment's notice, but many improvisers eschew props in favor of the infinite possibilities available through mime. In improv, this is more commonly known as 'space object work' or 'space work', rather than 'mime', and the props and locations created by this technique, as 'space objects' created out of 'space substance', developed as a technique by Viola Spolin. As with all improv 'offers', improvisers are encouraged to respect the validity and continuity of the imaginary environment defined by themselves and their fellow performers; this means, for example, taking care not to walk through the table or "miraculously" survive multiple bullet wounds from another improviser's gun.

Because improvisers may be required to play a variety of roles without preparation, they need to be able to construct characters quickly with physicality, gestures, accents, voice changes, or other techniques as demanded by the situation. The improviser may be called upon to play a character of a different age or sex. Character motivations are an important part of successful improv scenes, and improvisers must therefore attempt to act according to the objectives that they believe their character seeks.

In improv formats with multiple scenes, an agreed-upon signal is used to denote scene changes. Most often, this takes the form of a performer running in front of the scene, known as a "wipe". Tapping a character in or out can also be employed. The performers not currently part of the scene often stand at the side or back of the stage, and can enter or exit the scene by stepping into or out of the stage center.