Reversal is a technique used in a number of risk management activities such as risk treatments (e.g. managing customer experience risk: think what really bad customer service looks like, and work out what the opposite of that would involve), reverse stress tests (working out what might kill your business and then working backwards to find out how it might happen), and reverse needs assessments for strategy execution.
The D-Day landings 75 years ago involved huge amounts of planning with 156,000 troops landed from 5,000 landing craft, supported by 6 battleships, 104 destroyers, 277 minesweepers, and planes from 100 different airfields in Britain. An immense effort. And then there were all the deception exercises to keep the enemy guessing where the invasion was going to happen. The deceptions included an army massing in Scotland for a potential invasion of Norway or Denmark, disinformation created by the “Double Cross Committee” and fed to the Germans by double agents, and closer to the Normandy beaches, the dropping of thousands of dummies or scarecrows by parachute which successfully diverted a German division on the night of the actual invasion.
Despite the vast amount of ingenuity and planning of the assault on the Normandy coast, it appears that little thought had gone into what happened next. The British army’s day 1 objective was to take the city of Caen, but they had not prioritised the landing of the equipment they would need to do so (specifically “AVREs”, specially adapted Churchill tanks). This had several implications: territory was not taken to enable the RAF to establish airfields to operate from, German reinforcements had time to arrive, and casualties after the landings were far higher than on the landings themselves. It took a month and a half to liberate Caen at terrible cost to all sides, including the civilian population. It also caused political and reputational issues with the Allies.
In reverse needs assessment, you start with your objective having been achieved, and work backwards to ensure you have identified, and can put in place, everything you need to achieve it. It would have been helpful at Caen.
Source: “D-Day”, Antony Beevor.