I came across lots of good information on estimating unknown tasks in this stackexchange thread. Two main takeaways:
- Have you broken down the task into sufficient sub-tasks? The trouble with estimating may come from the fact that you are considering a large, complex task with many parts that you don’t fully understand. For example, “Build a shed”… the shed could be large, small, complex, simple: the trouble with estimating comes from insufficient thought about what the shed will be.
- A very useful formula to keep in mind: D = ((1 * OD) + (4 * ED) + (1 * PD)) / 6
- OD = Optimistic Duration
- ED = Expected Duration (your best guess)
- PD = Pessimistic Duration
- D = Most likely duration