How often have you been in a situation when your manager (customer, stakeholder, etc.) taps you on the shoulder and says something to the effect of:
Hey, Bob, I have this little project for you. Here is what I need (proceeds to describe scope at a very high level). How long do you think it would take your team to deliver this? Can you provide me with your estimate by the end of the day (week)?
Every project manager is aware of the fact that as soon as we said “project estimate”, we, whether we like it or not, said “uncertainty”. So here is a million-dollar question:
How to provide quick estimates when very little is known about the final product?
Option 1: Plus-Minus Qualifiers
Example: This project should take six plus/minus two months
Duration = 6 months ± 2 months
Option 2: Ranges
Example: This project should take anywhere between four and eight months
Duration = 4 months – 8 months
Option 3: Cases
- Best case – 4 months
- Most likely – 6 months
- Worst case – 8 months
Option 4: Coarse Dates and Time Periods
Example: “3 Quarters” instead of “9 months” (or 180 days)
Duration = 3 Quarters
Option 5: Confidence Factors
Example: “We are 90% sure that the project will be done in between 90 and 120 days”
And how do you present your project estimates? Please leave your comments below.
- Single number
- Plus-Minus Qualifiers
- Coarse Dates and Time Periods
- Confidence Factors