Estimation
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.
Webinar Replay Now Available: Successful Estimating Processes Using the SLIM API
If you were unable to attend our most recent webinar, Successful Estimating Processes Using the SLIM API, a replay is now available.
How do best in class development organizations achieve maximum return on investment from their estimation programs? By leveraging the SLIM API for integrations between estimation tools and detail-oriented products, development teams are able to simplify estimation processes and broaden the estimation program user base. Presented by Carl Engel of IBM Global Services, Scott Lancaster of State Street, and Larry Putnam, Jr. of QSM, this webinar explores two successful implementations of the SLIM API between third party tools and the SLIM Suite.
Software Cost Estimation Article in The DACS Journal
The February issue of the DACS Journal of Software Technology focuses on Software Cost Estimation and Systems Acquisition. My contribution, which you can read here, addresses the challenges faced by estimators and the value of establishing a historical baseline to support smarter planning, counter unrealistic expectations, and maximize productivity.
Using several recent studies, my paper addresses the following questions:
Part III: The Caveats
In Part 1 of How Much Estimation? we noted that there is an optimal amount of time and effort that should be spent in producing an estimate based on the target cost of a project and business practice being supported.
In Part 2: Estimate the Estimate, we saw that the formula to calculate this optimal time (as measured at NASA) calculates the Cost of Estimate as the Target_Cost raised to the power 0.35 (approximately the cube root of the Target Cost). The factor that defines the business practice (either by early lifecycle phase or perhaps by the “expected precision” of the estimate) is a linear factor ranging from a value of 24 to a value of 115.
Part II: Estimate the Estimate
In Part 1 of How Much Estimation, we observed that both too much time and effort and too little time and effort spent on estimating are less than optimal. Combining:
How Much Estimation?
How much time and effort should we spend to produce an estimate? Project estimation, like any other activity, must balance the cost of the activity with the value produced.
There are two extreme situations that organizations must avoid:
The Drive-By Estimate
The drive-by estimate occurs when a senior executive corners a project manager or developer and requires an immediate answer to the estimation questions: “When can we get this project done?” “How much will it cost?” and “How many people do we need?" (the equally pertinent questions: “How much functionality will we deliver?” and “What will the quality be?” seem to get much less attention).
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:
Why Does Project Size Grow?
Seen from an airplane window, the ground looks almost two dimensional. Only the largest features: cities, rivers, and mountain ranges, stand out against the background. The true complexity of the terrain only becomes apparent after we land and have to navigate through congested traffic, bad weather, and one-way streets.
Software projects are similar. Staffing and budget plans are often based on high level requirements that tell us what needs to be done, but not how to accomplish it. As business objectives are translated into the actions that need to be taken and the work products that must be produced, the size of the project, whether expressed in lines of code, function points, or RICEF objects, increases along with the time and effort required to create them.
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:
Introducing the SLIM-Estimate Certification Program
QSM is pleased to announce the SLIM-Estimate® Certification Program. Specifically designed to help our customers ensure the technical excellence of their SLIM users, this program increases the business value of our software project estimation tools to your organization.
How Certification Is Achieved:
In order to be awarded certification, a user must demonstrate competence in the following areas:
