So the Royal Baby® had everyone running sweepstakes on baby weight and gender and there was a ton of guessing. Weight guesses ranged from six pounds eleven ounces to eight pounds four ounces with many kinds of logic being explained about why the numbers were selected. There were some incredibly convincing statements about how the weight estimates were linked to Kate’s bump dimensions and plenty of anecdotal evidence where people with similar bump dimensions produced babies of certain weights.
Of course, all these estimates were wrong. All of them were less than the actual. More proof perhaps to support Hofstadter’s Law:
“Hofstadter’s Law: It always takes longer than you expect, even when you take into account Hofstadter’s Law.” – Douglas Hofstadter
So really the big question isn’t how can we estimate things accurately, the correct question is “how much do we want to spend on estimating compared to actually doing?”.
The amount of accuracy and precision you gain by increasing your estimation effort supplies diminishing returns, so just do something really simple that gives you good enough estimates… or maybe don’t even do it if it isn’t valuable for your organisation.