In this issue:
Do the people who ask you for estimates trust your estimates?
It's difficult to build trustworthy estimates. Here are three tips you can try for estimates that work for you, not against you.
Tip #1: Never provide a single-point estimate.
When people ask me for an estimate, I provide a percentage confidence or a three-point estimate. I use the percentage confidence when they want to know, “Can you meet this specific date or budget?” I can be very confident close to the end of the project and much farther away at the beginning of the project. When I say, “I have a 50% confidence in that date–that means I am sure we can get about half of the work done, but I am not sure at all about the other half,” the requestor understands the problem.
I often provide a three-point estimate when it comes to schedule. “This date is possible, but it's not likely. This other date is likely, but not guaranteed. I am very sure we can make it by this last pessimistic date.” People might not want to hear these qualifications on dates. In my experience, when you train people to hear estimates with reasons, they are more likely to trust your estimate.
Tip #2: Ask the people who will do the work to estimate.
Have you ever noticed that if some work is easy to discuss, some people think it's easy to do? If people outside your project estimate the apparently easy work, they might underestimate the work for your project team. If you make commitments to anyone based on those estimates, you could be in trouble before you even start the project.
You might discover over time that a specific team over- or under-estimates. If the team has that history, ask them if it's okay if you increase or reduce their estimate, based on history. Show them their history. And, try Tip #3.
Tip #3: Plan to iterate on your estimate as you learn more.
I wish the world didn't change when I have to estimate something. But, it does. You can change your estimate based on new information or changes. If you plan to estimate and explain to the people who want the estimate, “This looks like our estimate for now. I will know more in a month. Do you want another estimate then, after our demo?”
Now, you've set their expectations about what they will see and when you will update the estimate.
Creating estimates that people trust is difficult. You can persist and explain what your estimates mean. If you deliver working product as you iterate on your estimate, you build trust.
If you liked these tips, learn more with Predicting the Unpredictable: Pragmatic Approaches to Estimating Cost or Schedule. The book is available everywhere now, in ebook and print formats. (Those of you in Canada might have to wait a couple more weeks for print.)
If you are looking for information about estimating a large program, take a look at my book in beta: Agile and Lean Program Management: Scaling Collaboration Across the Organization.
I am speaking July 21 at Uberconf in Colorado:
* Design Your Agile Project
* Tuning Your Agile Team
See my calendar page for all my workshops and speaking dates.
Are you new to the Pragmatic Manager newsletter? See previous issues.
See my books page for my books. If you see one that interests you, and you would like me to speak about it, let me know.
Do you need a friendly ear and some sound advice? See my coaching page for my packaged and customizable coaching services.
See my workshops page for my workshops.
© 2015 Johanna Rothman
Tags: books, estimation, Predicting the Unpredictable, project management, trust