Laura Zuber's blog

Laura Zuber's blog

For More Accurate Software Estimates, Avoid Hidden Risk Buffers

A colleague of mine recently sent me a blog post explaining the difference between project contingency and padding.  The blogger made the distinction that padding is what often gets added to an individual’s estimate of the effort required to perform a task (in her example, a software development task) to account for project ‘unknowns’.  The estimator determines the most likely required effort, then pads it with a little more effort in order to arrive at an estimate to which he or she can commit.  Thus, padding represents an undisclosed effort reserve (and implied schedule reserve) to buffer against potential risk.  Contingency reserve, she explains, is “an amount of money in the budget or time in the schedule seen and approved by management.  It is documented.  It is measured and therefore managed.”  Ms. Brockmeier is correct in promoting contingency as the better management tool.  The challenge is having a method to measure and document this contingency and the known unknowns it is buffering.

Implicit Risk Buffer

Padding is a natural result of bottoms-up, effort-based estimation techniques.  Estimating low-level WBS elements creates more opportunity for padding, because the number of unknowns grows with the task list.  The estimator is consciously or unconsciously assessing the risk of each task, considering its dependencies and complexities.  What is being implied in the effort estimate is: 1] an assessment of product size and complexity, and 2] a productivity valuation.

Blog Post Categories 
Risk Management Estimation

What If? The Power of the Question

After being away from QSM and the software world for three years, I was blown away by SLIM v8.0's dynamic product integration. I knew it was coming, yet I was still impressed by the simplicity and power of analysis promoted by real-time data and tool links across the SLIM Suite that frees managers to focus on the important program issues.

SLIM-MasterPlan is the center of the SLIM Suite product integration.  It improves upon previously existing program management features of aggregating multiple SLIM-Estimate projects and ancillary tasks with two new capabilities: 

  • Linking SLIM-Control workbooks to provide real-time project tracking and control at the program level 
  • Performing What If analysis at this higher management view to consider a wider range of potential outcomes.

The What If analysis feature is what I want to highlight.

A good personal development coach knows the "power of the question."  Questions lead to discovery, innovation, and action that brings about positive change.  Better questions lead to better answers.  SLIM's power and distinction has always been fast and easy evaluation of the impact of change, and exploring the realm of possible outcomes.  That's what we are doing when we ask ourselves "What If…?" (or our boss asks us - and we better know the answer!).  SLIM's solution logs make it easy to compare estimates, plans, and forecasts to alternative solutions, QSM trends, and your historical project database.

Two Tools Are Better Than One

Have you ever been excited to discover a new use for something familiar, like learning that lighter fluid can be used to remove ink stains from your clothes?  I recently discovered a way to leverage the tie between SLIM-Estimate and SLIM-DataManager that I was previously unaware of.  

My limited view of SLIM-DataManager as a tool for historical data and SLIM-Estimate as a tool for software project estimation limited my creativity in applying the rich set of capabilities in the entire SLIM tools suite.  I recently observed a more experienced SLIM user use both tools to model a history project where very little data was available, using both applications.  Here is a description of the situation.

Scenario: 

You have gathered metrics from a completed project to serve as the basis of estimation for your next project.  Software size, lifecycle effort, lifecycle duration (phases 1-3), and defects are known, but you do not have a break out of individual phase data.  How can you best model this project and capture the results in SLIM-DataManager?

Solution A: 

Blog Post Categories 
Estimation Tips & Tricks