Expert Judgment and Passing the Sniff Test


Looking for two very informative posts on estimating?  Check out one by Josh Nankivel of pmStudent and Glen Alleman of Herding Cats.  Both are discussing estimating techniques that work for them.

I wanted to take a moment to add my two cents. Though I certainly believe estimating should be more science than art, I look at estimates from a different perspective. As a disclosure, I’m not the one doing the estimating on this project, therefore I’m not going to say I agree or disagree with any one technique.  Depending on your situation, one estimating technique may provide more accurate results than the other.

What I would like to add, from my perspective, is the need for expert judgment. If you are an expert in a given estimating technique and it gives you the results you and your customer(s) need, does that not validate it as an acceptable estimating choice?

If the estimating technique does not produce the desired results, wouldn’t it fail the metaphorical sniff test?

Recently, I questioned a vendor’s estimate based on a different technique.  I used a parametric estimate to see if the vendor’s estimate would pass or fail my sniff test.

What exactly is a parametric estimate?

An estimating technique that uses a statistical relationship between historical data and other variables to calculate an estimate for activity parameters, such as scope, cost, budget, and duration.  Source: PMBOK Page 439

So, why did the vendor’s estimate not pass my sniff test?  As part of a standard estimating practice, software vendors should include time for fixing bugs. Upon review of a recent status report, I noticed the vendor reporting half as many bugs were discovered in a current build than had been estimated. When asked about this, the vendor was very excited to confirm that they indeed found half as many defects in the code they originally estimated and predicted a cost savings of several hundred thousand dollars to the project.  Going into the current build, I knew what the standard deviation was and considered the possible variance.  This fell way below that.

So, why were they discovering so few bugs?  At first glance, I would predict two possible reasons.  [1] Quality through development improved.  [2] Quality through testing worsened.  Either way, you get the same initial result of fewer defects identified.

We’ll know the true answer once initial user acceptance testing begins.  If there were no baselines to compare the actuals to, I might not have given it a second thought.

Graphic source via Flickr: pump

Team Building Techniques – 5 Stages

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When I think of team building techniques, the one place I didn’t think to look was the PMBOK®. In chapter 9, specifically 9.3.2, the PMBOK details Tools and Techniques of Developing Project Teams. For those out there studying for the PMP®, this might be a good time to write this down or print the blog post.

The PMBOK lists 5 stages of development that teams may go through, usually occurring in order.  What PMBOK lists is relatively academic.  It won’t actually help you with team building.

Those stages, with the exception of the last are based on the Tuckman ladder[1].  Forming – Storming – Norming – Performing. It’s a model of group development, first proposed by Bruce Tuckman in 1965, who maintained that these phases are all necessary and inevitable in order for the team to grow, to face up to challenges, to tackle problems, to find solutions, to plan work, and to deliver results.

Why PMI found it necessary to add the last one, I can’t tell you.  But, in the event you think it may appear on the PMP exam, here is what PMI thinks you should know.

Forming. This phase is where the team meets and learns about the project and what their formal roles and responsibilities are. Team members tend to be independent and not open in this phase.

Storming. During this phase, the team begins to address the project work, technical decisions, and the project management approach.  If team members are not collaborative and open to differing ideas and perspectives the environment can be destructive.

Norming. In the norming phase, team members begin to work together and adjust work habits and behaviors that support the team. The team begins to trust each other.

Performing. Teams that reach the performing stage function as a well-organized unit.  They are interdependent and work through issues smoothly and effectively.

Adjourning. In the adjourning phase, the team completes the work and moves on from the project.

The PMBOK concludes by saying a Project Manager should have a good understanding of team dynamics in order to move their team members through all stages in an effective manner.

Two stages I think they missed include  Empowering and Supporting.  If PMI can insert Adjourning into this list, with the sounds of One of these things is not like the others in my head, I think I can add my two stages.  Still, if you want to pass the PMP, perhaps you should just stick to their list.

[1] Tuckman, Bruce, 1965. Developmental Sequence in Small Groups. Psychological Bulletin No. 63. Bethesda, MD: Naval Medical Research Institute.
Image source: Orange Country Register