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Better Estimation Means Better Projects
Dr. Christof Ebert is managing director at Vector Consulting Services
OCT 12, 2012 10:45 AM
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Better Estimation Means Better Projects 
 
Estimating size or resources is one of the most important topics in software engineering and IT. You will not deliver according to expectations, if you don’t plan. And, you cannot plan if you don’t know the underlying dependencies and estimates. 
 
An estimate is a quantitative assessment of the likely amount or outcome of a future endeavor. It is usually applied to forecast project costs, size, resources, effort, or durations. Often estimates are confused with goals or plans. For instance, projects are scheduled according to needs but not in line with feasibility. Or commitments are given to clients on something “very urgent and important” before having checked how this “urgency” relates to the already taken commitments and capacity planning. In fact most failures in software projects come from now understanding and considering this important difference between goals, estimates and plans. It is thus important to first understand these three different perspectives. 
 
Four families of estimation techniques have evolved and are today used in industry practice, namely expert judgment, analogy, decomposition, and statistical (or parametric) methods. COSMIC function points have proven an excellent and rather widely applicable technology for estimating effort and size across industries. There are only few really useful estimation tools on the market, namely KPlan, QSM, CoCoMo and Seer. This is due to the high effort collecting all the raw data. The tool is no substitute for manual systematic data collection, planning and controlling – in each single project. We face, with at least half of our clients, insufficient estimation and thus unnecessary high cost and missed opportunities for cost reduction.
 
Here is some guidance for improving your estimates:
• Collect your own data on a regular basis and at the right level of granularity. 
• Use a single source for all relevant measurement from all projects.
• Plan based on estimates, and execute based on plans. 
• Think balanced scorecard and use a set of mutually supportive measurement dimensions.
• Target an estimation accuracy in line with your business needs. 
• Use estimation tools to grow. 
• Challenge your own productivity and cost drivers. 
• Improve your efficiency each year with concrete improvements.
 
From our own experience, the right moment for implementing estimation and measurement is now! We experience many clients who after a year can improve their preciseness to 10-20%, which in most cases is sufficient. Start now and then proceed with improving data quality, estimation precision and of course your efficiency. Or in the words of famous E. Deming: “In God we trust. All others bring data.”
 
More:
The book “Software Measurement. Establish, Extract, Evaluate, Execute” from Springer, provides a good introduction to measurement and estimation.

URLs:

IEEE Software: http://www.computer.org/portal/web/csdl/doi/10.1109/MS.2011.55

COSMIC function points: http://www.cosmicon.com

White Papers and resources: http://www.vector.com/software-measurement

Author:

Dr. Christof Ebert is managing director at Vector Consulting Services. He supports clients around the world to sustainably improve product strategy and product development and to manage organizational changes. An IEEE senior member, he serves on a number of advisory and industry bodies and lectures at the University of Stuttgart.

Contact him at christof.ebert@vector.com

 
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