By Mohit “Mo” Sahgal

In this penultimate estimation blog installment, I will review the purpose and benefits of estimating models. Without a proven estimating model, what confidence can anyone have in the estimates? Factors, formulas and methodology form the basic ingredients and recipe. Scalability is achieved through on-going harvesting, calibration and corroboration. This helps builds historical context and an expertise knowledge base.

Higher-performance can be achieved when the models account for:
1. Additional levels of complexity
2. Task-level contingency
3. Productivity or work effort improvements
4. Work effort distribution across multiple locations
5. Sub-contracting, third-party or teaming partner interdependencies
6. Phased deployment or release scheduling
7. Technology specialization
8. Staffing pyramids for different types of workforces
9. Site-specific service introduction
10. Production support maintenance and warranty

What precision is required? The best that is possible. If precision is not a priority, then why estimate? If estimates are not priority, then why plan? Precision doesn’t mean estimating the work effort to the hour; precision means estimating the work effort within generally acceptable tolerances. What is the goal? In general, during strategy planning phases, rough order magnitude (“ROM”) estimate ranges may have larger tolerances of between -10% and +25%. The Project Management Institute (PMI) has established “definitive” guidelines as the output of the Planning phase to be at -5% to +10%. As estimation calibration improves, organizations should expect these lower and upper tolerance levels to narrow – improving precision and confidence in project delivery.

In the next blog, I will review the resources and competency required to estimate, and summarize the entire estimation blog series with some more insights.


Mr. Mohit “Mo” Sahgal is the VP of Analytics of Paradigm Technology. He is an accomplished Senior Executive with decades of management consulting expertise. Mo has held various leadership positions including Senior Executive at Accenture, Partner at IBM, Partner at Capco, and Executive Director at Ernst & Young LLP.

Mr. Sahgal LinkedIn profile can be found here.

 Paradigm Technology is a strategic consulting company serving the utilities, banking, airline, manufacturing and high-tech verticals.  We utilize innovative business and technology solutions to help clients enable their digital transformation programs, and improve their Analytics, Cloud, Master Data Management, and Project Leadership solution delivery. Paradigm is ready to support you in your business journey.  For more information about Paradigm Technology, email or visit us at