TOC Terms and Concepts

A flow that typically begins with a larger number of raw materials that are combined as they proceed through production, ending in fewer number of finished products. Most “A” Flows are typically assembly operations. Examples: Specialized equipment manufacturers, airplanes, large generators/ motors, consumer electronics, etc.   Source: Oded Cohen and Jelena Fedurko, Theory of Constraints […]

Analysis of Current Reality and Solution for Future Reality with U-shape

The U-shape is a comprehensive logical diagram of TOC entities that participate in the analysis of the current reality and the construction or usage of the solution to create an improved future reality. The U-shape was established to organize, store and easily retrieve the TOC knowledge. The U-shape is used for the generic TOC solutions […]

Assumption Rules for straight arrows A-B, B-D, A-C, and C-D’ – 4 Rules

Four Assumption Rules for straight arrows A-B, B-D, A-C, and C-D’ Rule 1 – Referring words 2 checks: (1) The statement after “because” should contain some words that clearly refer to the “in order to” part of the statement, and some to the “we must” part. (2) Make sure that the assumption is bringing in […]

Assumption Rules for the conflict arrow D-D’ – 2 Rules

Two Assumption Rules for the conflict arrow D-D’ D-D’ Rule 1: Surfacing Rule “D AND D’ are in conflict because…” D-D’ Rule 2: What is missing?   Source: Jelena Fedurko, Mistakes and Difficulties in Working with TOC Logical Tools, 2014


Assumptions are facts, observations, beliefs, expectations, convictions, presuppositions, experiences, interpretations, concepts, principles, data, general knowledge and other elements of thinking with which we support our reasoning behind a logical connection. Source: Jelena Fedurko, Behind the Cloud: Enhancing Logical Thinking, 2011