How do you give a valid time estimate for something you have never done?

Question

As a new developer who is the only software guy on staff I have faced a few challenges but possibly the most difficult has been time estimates. I strugle every time I have to give a project estimate.

My question then is; If I do not have any experience and I don't have a fellow dev in my environment, how do I provide a solid estimate? I have read Joel Spolsky's article on Evidence Based Scheduling but how can that apply if I do not have any evidence?

I appreciate any advice on this subject.

Answer 1

You don't provide a solid estimate. You give as good an answer as you can, and explain that it is just a very rough estimate, and why it's so rough.

If you make it very clear that:

• You can't give an accurate estimate
• It's entirely reasonable that you can't give an accurate estimate because it's different work to what you've done before
• You'll update the estimate as time goes on and you get to know the topic better

I think you should be okay. You need to make those things very clear though, in writing, so that you don't get held to your rough estimates later.