Custer, Gallipoli, and the Planning Fallacy

“Man plans, God laughs” – Yiddish Proverb


We’ve all heard it…”What does your project plan say?”…”Does this match your plan?”…”Have you written a plan?”  An outsize component of enterprise IT is the creation and reliance on a project plan.  For many organizations the existence of a plan is paramount to success in any endeavor.

I posit that almost every agile practitioner has heard some semblance of “How can you deliver if you don’t have a plan?” multiple times across multiple engagements.  For the organizations steeped in the traditional method of project delivery the thought of having a plan means that everything is operating in control.  But that’s not true, is it?


The best laid schemes of mice and men go often askew” – To A Mouse, Robert Burns


In 1979 Daniel Kahneman and Amos Tversky first proposed the planning fallacy.  They propose a phenomenon where predictions about how much time is needed to complete an endeavor is always underestimated due to an optimism bias.  This definition was expanded in 2003 to include not only time but also costs and risks.

Most practitioners have come across the planning fallacy at some point, but I don’t think the definition goes far enough.  This definition does not cover the “blind spot” that organizations willfully create when they say “We have a plan, we’ll stick to that plan and be O.K..”  

I say that the mere existence of a project plan itself leads to false hope!

How many times have you seen a manager/executive make decisions solely on either the existence or contents of a project plan?  How many times have those decisions been wrong, or gone awry?  How many times(in the rare instance that a waterfall project actually DOES a post-mortem/retrospective) has someone said “How did we miss that in the plan?”

But it’s not just technology…there are numerous examples throughout military history where “if things had gone to plan we would’ve won!”  For example:


  • Custer’s Last Stand at Little Bighorn – Custer estimated the number of combatants to be around 800, when in actuality it was closer to 2,500.  Custer also refused to utilize a Gatling gun battery fearing the weight would slow his progress (“I understand the risk, but I’m not putting that in my project plan.”)  He also divided his forces into smaller detachments that could not efficiently support each other during battle.  
  • Gallipoli Campaign, World War I – The approach was to land in the Dardanelles and to push inland to Constantinople.  Military planners overlooked that they would be fighting uphill against a fortified enemy (“How did we miss that in the plan?”), and the initial landings were pushed further north than planned due to currents and/or navigational error.  What followed was a campaign that ran almost a year, extracted heavy casualties, and resulted in a retreat.
  • Napoleon invading Russia – Napoleon is widely regarded as a military genius but he will always be remembered for attempting to attack Russia during the winter (over-optimistic expectations of task duration).  This was the straw that broke the camel’s back and led to his eventual undoing.  And in an ironic twist, Hitler attempts to do the same thing in World War II with the same result.
  • Dien Bien Phu, First Indochina War – The French plan was to lure the Vietnamese combatants out and then overtake them with their better weapons/training/tactics.  The generals forgot to include that they would be surrounded by mountains and could only be resupplied by air (again, over-optimism).  The Vietnamese dug-in to the surrounding hillsides with artillery batteries and through a slow and steady pace eventually defeated the French.
  • Operation Eagle Claw – In 1979 Iran overtook the American Embassy and claimed 52 hostages. President Carter and his generals came up with a plan to rescue them using the Army’s Delta Force commandos.  The operation encountered numerous mechanical failures for multiple reasons and the mission was scrubbed (“That wasn’t in the plan, it wasn’t supposed to happen!”).  To add insult to injury 8 servicemen were killed during the extraction due to poor visibility as a result of blowing sand.


While I would love to throw out the whole idea of creating a project plan in all honesty that will never happen.  And to be completely frank, the activities around creating a plan can bear fruit as they often uncover items or options that might not have been considered previously.  This exercise typically provides more value than the plan itself!


“…plans are useless, but planning is indispensable.” – Dwight D. Eisenhower


If you are going to put in the effort to create a plan, you need to make an equal or greater effort to review and adapt the plan to things you’ve learned as time progresses.  In agile terms we speak of relentless improvement; we speak of continuously improving based upon looking back at performance and honestly appraising it along with making changes.  This same behavior and activity should be applied to planning (if you must make a plan 🙂 ).

Project plans are a waterfall artifact that will most-likely never go away.  If we remain vigilant for the potential blind spots that these documents can create as well as make an effort to continuously refine these plans, there’s a good chance that we can succeed no matter what the plan says.