Estimates versus Commitment
If you are a member of development team, sooner or later someone will ask you to estimate something. It can be something small like a bug or task but it can be also something bigger like entire project. Regardless what that is, try to figure out what kind of answer you are expected to give. I don’t mean here that you should be trying to give the “right” estimate. I’m thinking about something different — usually there are two possible types of answers:
- We need 12 to 18 weeks for this project.
- We need 4 developers, 1 interface developer and 2 testers to have this project done before …. (some fixed date)
In the first case … you were really asked to give unbiased estimates, deadlines don’t exist for you. Project plan and deadlines will be planned based on estimates and negotiations with a client.
Second type is more interesting. It indicates that estimates are not the final objective, there is something more. Target (deadline) for this project is already set up front. So the real question here is “Can you come up with a plan to meet the deadline?” To answer it you need estimates, to provide a plan it’s good to know how big the project is. However keep in mind that it is only an intermediate step. It’s better to be very careful with this type of questions because even though you were asked for estimates, in fact it was a question about a commitment. By saying that you need given number of people to get something done, you are in fact giving your word that it can be done. If you don’t believe me then let me rephrase the second answer without changing the meaning into something like this “Sure, we can do it before … (some fixed date), we just need a team of 4 devs, 1 interface dev and 2 testers” 
That’s why I think whenever someone asks you for estimates, it’s always good to check if the question is really about estimates or maybe it’s about a plan to meet the target.
What’s the relation between estimates and commitment?
Commitment is a promise to finish agreed functionality in given time. It doesn’t have to be the same as estimate. When you truly need to win a contract with a high-profile client then commitment can be more aggressive than estimates. You may assume that this contract will be a first step to a longer relationship and accept higher risk. On the other hand when you know about number of integration points and expect problems with them, you may want to go with more conservative commitment.
Second answer could be more like this: “We need 5 devs and 2 testers to deliver the product with at least the most important set of functionality by given fixed date”.
Life shows that fixed date is driven by some business and/or marketing constraints and there is always a space to operate on scope.
Then comes the whole art of Product Owner work and ability to explain that there’s always uncertainty in the project (i.e. constant changes) and having date plus cost fixed, we must have possibility to modify and manage scope as we go along but still aiming at business success of the project.
It’s a matter of building trust with a client.
Regarding ‘commitment’ – I generally think no one should commit to anything beyond the current sprint
Bartek Papierski
13 Aug 10 at 12:01 am
@Bartek
“fixed date is driven by some business and/or marketing constraints and there is always a space to operate on scope”
I do agree. There are cases when clients claims that given project is fixed date and scope but usually date has higher priority so there is a room to manage client’s expectations.
“Regarding ‘commitment’ – I generally think no one should commit to anything beyond the current sprint”
That would be perfect, but I think on fixed price projects we are forced to go beyond that.
Marek Blotny
13 Aug 10 at 7:30 am
@Marek if fixed price project has fixed date and scope, we have problem and something is going wrong with client relations/negotiations. What you eventually can commit to is price and/or date for fixed price /date project or scope for fixed scope project. But never commit to all of them.
Generally, if you have to commit to anything beyond Sprint, be caucious and talk as much as you can to the client to be sure her understanding is finally same as yours.
Bartek Papierski
19 Aug 10 at 7:46 pm
[...] In one of the previous post I was writing about estimates and commitments. I felt that this is an important topic because life shows that very often deadlines are beyond our [...]
Deadlines – Is There a Room To Negotiate Them In Web Development Industry? at Marek Blotny's Blog
26 Aug 10 at 7:09 am