Blog
Mert Özen's blog posts on software development, backend, frontend, and DevOps.
Communicating Estimates and When the Plan Slips: Updating, Delivering Bad News Early and Replanning
When a plan slips, the first move is to deliver the bad news right away together with options; choosing between cutting scope, moving the date or adding people is a business decision, and adding people to a late project rarely saves the date. Bookstore's update after three sprints shows scope grew to 142 points and the full scope slipped to March 26; we compute the options in C# and write a one-page estimate note.
Risk Management in Software Projects: Pre-Mortem, Risk Register, Probability × Impact and Retiring Risk Early
Managing risk means surfacing it early with a pre-mortem, comparing probability × impact with the buffer and putting the riskiest work at the start of the plan. In Bookstore's Institutional Orders register, total exposure is 21.6 days, more than the scope buffer; an ERP spike and pair work bring it down to 4.9 days in three sprints. We cover ROAM, risk burndown and risk vs issue with C# code.
Release Planning: Velocity Ranges, Burn-Up, Fixed Date or Fixed Scope?
A release date comes not from one average velocity but from a range derived from past sprints; if the date is fixed, scope flexes in MoSCoW layers. Bookstore's 130-point Institutional Orders plan lands between February 12 and March 12, and the Must scope fits by March 1 even in the bad case. We also answer the same question with Monte Carlo and see why the two methods disagree.
Estimation Beyond Points: Three-Point/PERT, Wideband Delphi, Work Breakdown and Reference Class Forecasting
To estimate uncertain work, break it down, give each piece three points, simulate the total instead of adding numbers up, and check the result from the outside against how similar past work drifted. For Bookstore's bulk order slice, a C# simulation shows the sum of most likely durations (21 days) holds only 3.1% of the time, the 85% value is 28 days, and the figure corrected with past epics is 34 days.
Story Points and Relative Estimation: Planning Poker, T-Shirt Sizing and the Contested Legacy of Story Points
Story points help because comparing pieces of work is easier than estimating duration; they hurt when points are converted to hours, compared across teams or made a performance target. We cover planning poker, t-shirt sizing and #NoEstimates with 10 sprints of Bookstore data: points and story counts correlate at 0.81, but counting stays optimistic because the new epic's stories are bigger.
Why Software Estimates Go Wrong: Estimate vs Target vs Commitment, the Cone of Uncertainty and the Planning Fallacy
Estimates go wrong because they are usually given as a single number, at the most uncertain moment and from an optimistic scenario; the honest answer is a range, a confidence level and assumptions. We cover estimate vs target vs commitment, the cone of uncertainty and the planning fallacy with C# code that processes the Bookstore team's estimation history for 12 features.