PEST Analysis is used to assess the market environment for a business.
There are variations of the model which identify other factors, although some researchers argue that those additional factors are just aspects of the main four. Variations include reorganization of the letters (ESTP, STEP) or the addition of Legal, Environmental, Ethical, Legislative, International, Industry, or Demography (PESTLE, STEEP, STEPE, STEEPLED, PESTELI).
Business Monitor International
Icon Group International, Inc. (no longer included?)
IHS Global Insight, Inc.
MarketLine, a Datamonitor business
OECD: Organisation for Economic Cooperation & Development
PRS Group, Inc.
Superintendent of Documents