Why do new project managers fail at estimating task durations accurately?

All answers to this question.

New PMs almost always estimate based on the ideal scenario where nothing goes wrong, no one gets sick, and servers never crash. This is known as the planning fallacy. You are likely asking developers for estimates and taking their best-case answer as gospel truth. Experienced managers know that developers are notoriously optimistic. You need to add a buffer percentage, look closely at historical data from past similar projects, and use estimation techniques like Three-Point Estimating to give yourself a realistic safety net.

   Answered 2025-11-14 by Stephanie Kraft

Should we be using historical data from previous company projects instead of relying solely on guesswork, even if the technology stack has changed slightly?

   Answered 2025-11-18 by Jeffrey Riggs

• Yes, Jeffrey, historical data is vital. Even with a different tech stack, human behavioral patterns regarding delay remain similar. Comparing past velocity to current goals prevents you from repeating the exact same scheduling mistakes.

     Commented 2025-11-20 by Heather Mcclure

A frequent error is forgetting to factor in non-working time like company meetings, holidays, code reviews, and administrative overhead.

   Answered 2025-11-22 by Patrick Conley

• So true, Patrick. Newbies think an eight-hour workday means eight hours of pure coding or building, when it is usually closer to five or six productive hours.

     Commented 2025-11-25 by Stephanie Kraft