On the difficulties of estimating and keeping the project within the proposed time frame, the following “programming pearl” was published in 1985 and belongs to Tom Cargill of Bell Labs: “The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time.“ Hopefully, your estimate will not be off by 80%, but this is a quote you should always remember when estimating projects.
On the same page with the first quote, a self-referential one, coming from the book Gödel, Escher, Bach: An Eternal Golden Braid (isn’t that an impressive title for a book?) by Douglas Hofstadter, here it is the Hofstadter’s Law: “It always takes longer than you expect, even when you take into account Hofstadter’s Law.” Why people tend to think that it will take less to complete a project than it actually does? Probably because of the optimism bias – a cognitive bias that causes a person to believe that they are less at risk of experiencing a negative event compared to others.
For projects that are late, it would seem a good idea is to add more people to the project. Well, it’s not. In “The Mythical Man-Month”, Fred Brooks states the Brook’s Law: “Adding manpower to a late software project makes it later.” Derived from his first hand experiences while working at IBM, Brooks became so dissatisfied with people repeating his mistakes over and over again that he said his book is like the “The Bible of Software Engineering” because “everybody quotes it, some people read it, and a few people go by it”. Wait, what, was I just doing that?!
C.N. Parkinson, a British historian but who touched also public administration and management subjects in his books, came up with a few laws, including the one bearing his name, Parkinson’s Law: “Work expands to fill the time available.” So be careful with lax deadlines and estimates, because most times it will not translate into work being ready ahead of the deadline, as you would expect, but it will be actually contra-productive.
The Stock–Sanford corollary to Parkinson’s law states that: “If you wait until the last minute, it only takes a minute to do.” So go ahead and cut those deadlines (at least your personal ones), not to a minute, but maybe in half as recommended in this Lifehack article.
And I will end with the last law for today, Golub’s Second Law of Computerdom, a law that states why carefully planning a project is important: “A carelessly planned project takes three times longer to complete than expected; a carefully planned project takes only twice as long.”