Michael Barkun has identified three classifications of conspiracy theory:
- Event conspiracy theories. This refers to limited and well-defined events. Examples may include such conspiracies theories as those concerning the Kennedy assassination, 9/11, and the spread of AIDS.
- Systemic conspiracy theories. The conspiracy is believed to have broad goals, usually conceived as securing control of a country, a region, or even the entire world. The goals are sweeping, whilst the conspiratorial machinery is generally simple: a single, evil organization implements a plan to infiltrate and subvert existing institutions.
- Superconspiracy theories. Such theories link multiple alleged conspiracies together hierarchically. At the summit is a distant but all-powerful evil force.