Why are software development estimates regularly off by a factor of 2-3?
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Re: Why are software development estimates regularly off by a factor of 2-3?
#2Imagine you are going on a hike to the top of a mountain. Countless paths exist between you and your destination. Most of these are dead ends. Every dead end forces you to backtrack, sometimes all the way to the beginning.
Software is a lot like that.
Re: Why are software development estimates regularly off by a factor of 2-3?
#3Kept waiting for the punchline where the friend has moved to Las Vegas and a total replan is required.
Re: Why are software development estimates regularly off by a factor of 2-3?
#4Imagine you are going on a hike to the top of a mountain. Countless paths exist between you and your destination. Most of these are dead ends. Every dead end forces you to backtrack, sometimes all the way to the beginning. Software is a lot like that.
Then, on that Hike - Someone decides that the fastest way to the top is to hire 2-3 more guides. But before you can give those guides any meaningful work, you have to take them through all the previous bad paths...
Re: Why are software development estimates regularly off by a factor of 2-3?
#5Because management looks at you funny when you say something simple will take 4 months. Then they lie and say that it couldn't possibly take that long. And the reason they lie is because there's no negative to them tying to you. Their job is to get you to go faster, and they are allowed to lie as part of their job, if it makes you go faster. The reality is that it doesn't make people go faster. It makes people leave faster. It makes people give up.
Never give an estimate to management. Estimating is their job, as they control the inputs to production. If you give an estimate, they will pressure you to meet it, no matter how unreasonable it later turns out to be. That also makes people want to leave.
Re: Why are software development estimates regularly off by a factor of 2-3?
#6I admit it's funny but if I showed this to a non-programmer friend, he'd be asking why I didn't research my route better or start on an unknown trail with minimal planning.
Re: Why are software development estimates regularly off by a factor of 2-3?
#7Imagine you are going on a hike to the top of a mountain. Countless paths exist between you and your destination. Most of these are dead ends. Every dead end forces you to backtrack, sometimes all the way to the beginning. Software is a lot like that.
Then whoever was planning the hike decides to go to a different peak when you're halfway up the mountain.
Re: Why are software development estimates regularly off by a factor of 2-3?
#8Kept waiting for the punchline where the friend has moved to Las Vegas and a total replan is required.
"Oh it's just one state over, I didn't think it mattered. See you tomorrow!"
Re: Why are software development estimates regularly off by a factor of 2-3?
#9I just don't know why people won't arbitrarily add 2-3 more time on the estimate...
Re: Why are software development estimates regularly off by a factor of 2-3?
#10It's simple. People don't like the honest answer.
As a developer, I have pressure to keep my estimate down. I can give you a guaranteed date with few problems, but the project is going to end up more time-consuming than what another developer is going to estimate.
The good news is that I will usually significantly beat my estimates under this system. However, I will then be accused of padding my estimates and will be given more aggressive targets, some of which I will miss.
The best way to combat this is to give me a team that has worked together on multiple projects within the domain, and account for changes and ambiguities as part of the process.