I recently came across the following quotation by the American aviation pioneer Wilbur Wright in a speech to the Aero Club of France in 1908:
I confess that in 1901 I said to my brother Orville that man would not fly for fifty years. Two years later we ourselves made flights. This demonstration of my impotence as a prophet gave me such a shock that ever since I have distrusted myself and avoided all predictions (their first successful flight was in 1903).
Our ability to predict future outcomes is at best limited. As Robert Burns wrote in his ‘Ode to a Mouse’: The best laid plans of mice and men often go astray. Or more accurately (but unintelligibly):
In proving foresight may be vain;
The best-laid schemes o’ mice an ‘men
Gang aft agley,
For the full poem see: http://www.robertburns.org/works/75.shtml
But most of our project stakeholders expect predictability, we predict budgets time frames and delivery dates and they expect us to deliver. The challenge for us all is to effectively manage these expectations – unrealistic expectations are unlikely to be fulfilled.
Prediction is very difficult, especially about the future*. Setting fixed budgets and delivery dates without adequate contingencies is a recipe for failure. We have developed a couple of white papers on cost and duration estimating that may help develop realistic and achievable targets for your projects:
* Niels Bohr, Danish physicist (1885 – 1962)