What is Parkinson’s Law?
Parkinson’s Law is a rampant idea, though many don’t know the idea by this name. Parkinson’s Law states that:
“Work expands so as to fill the time available for its completion”
Parkinson’s Law was proposed by Cyril Parkinson in 1955 in a satirical article that mocked government bureaucracy, so it was likely never intended to be taken seriously. 
However, this idea often has legs. After all, we’ve all had experiences where a time crunch inspires an amazing amount of work to be completed in a short amount of time. Maybe you managed to learn a semester’s worth of material in the week leading up to the final exam. Or had a project with a tight deadline that inspired a heroic effort.
Or perhaps you’ve been on the flip side of this law, where work without a deadline expands:
Parkinson’s Law is Supported by Science
Evolution Research Sets the Stage
It turns out that Parkinson’s Law is actually supported by science. The story beings with research on evolution from Niles Eldridge and Stephen Gould.
The prevailing theory of evolution was that it occurred in a smooth, upwards progression. Eldridge and Gould discovered that for many species, evolution was not a smooth progression, but long periods of relative stability with short bursts of change. This is called the “punctuated equilibrium” model:
Gersick Discovers the “Uh Oh Effect”
Connie Gersick was researching organizational behavior to discover how teams complete projects. She studied 8 groups of teams of various size (3-12 people), different project lengths (7 days to 6 months), across different domains.
She found that progress was not linear like the phyletic gradualism model. Instead, the groups made progress that resembled the punctuated equilibrium model – long stints of stagnation followed by bursts of intense progress. 
The interesting finding is that what prompted the shift was consistent across the groups. It was the halfway point of the deadline.
We call this the “Uh Oh Effect” – seemingly halfway through the course of the project, the teams collectively said “Uh oh,” and adjusted their approaches to allow more effective progress.
How to Leverage the “Uh Oh Effect” for Agility
People don’t like to talk about Parkinson’s Law, or the “Uh Oh Effect” in the context of organizational Agility because it often promotes waterfall-like behaviors. Leaders use this idea to set overly-ambitious deadlines for big chunks of work to ensure that work gets done in a timely manner:
This is inherently waterfall behavior, but I also argue that it’s inefficient. Remember, based on Gersick’s research, that regardless of project length, the first half of the project is largely ineffective. Only at the temporal midpoint does the team say “Uh oh,” and identify more effective ways of working, and make huge movement forward in a punctuated equilibrium type of progress.
I believe knowing about Parkinson’s Law and the “Uh Oh Effect” should lead us to thinking in smaller units of work and smaller time blocks. Remember, that the first half of the timebox isn’t very effective, regardless of the size of the timebox. So use smaller timeboxes to increase the numbers of “Uh Oh’s” that your team gets.