Planannahmen

Planannahmen is a term used in planning theory to denote the set of assumptions that underpin a plan. The word combines Planen (to plan) and Annahmen (assumptions) and is used in some German-language planning literature to foreground the conditional nature of planning efforts. It refers to the future states of the world that must hold for a plan to be feasible, affordable, and desirable.

A Planannahmen document typically lists the key conditions and uncertainties that influence decisions, such as economic trends, demographic developments, technological progress, regulatory environments, funding availability, timelines, and stakeholder behavior. It may also cover design parameters, dependencies, external risks, and acceptable tolerances. The purpose is to make implicit premises explicit so they can be examined, contested, and revised as needed.

In practice, Planannahmen support feasibility assessments, risk analysis, and scenario planning. They help planners explain why a project is proposed, how success will be measured, and where plans may fail if conditions change. The process usually involves identifying assumptions, documenting their rationale and confidence levels, and establishing monitoring mechanisms to detect shifts. When significant assumptions change, plans should be updated or alternative courses of action prepared.

Critics note that Planannahmen can mask bias or overconfidence if not transparently presented and regularly reviewed. To mitigate this, teams often pair Planannahmen with sensitivity analyses and scenario variants, ensuring that planning remains robust under a range of future conditions.