Why estimation struggles at scale, and what delivery leaders can use instead.

55 Degrees
13 hours ago
3 min read

Estimation is deeply embedded in how many organisations plan and talk about delivery. It provides structure, numbers, and a sense of control in environments that often feel uncertain. For Delivery Leaders, estimation can feel like a necessary tool, something that helps align teams and reassure stakeholders.

Yet, despite careful planning and repeated estimation, predictability often remains elusive.

Many Delivery Leads recognise the pattern. Plans are revisited. Timelines are adjusted. Explanations are repeated. Even with detailed estimates in place, delivery still surprises us, and not in good ways. This disconnect creates frustration for teams, stakeholders, and Delivery Leads alike.

The problem usually isn’t bad estimation. It’s what estimation is being asked to do.

Story points and similar techniques were originally designed to support team-level conversations. They help teams discuss complexity, surface assumptions, and build shared understanding. Used this way, they can be valuable.

Trouble starts when estimates are stretched beyond that context.

As delivery responsibility expands across teams and initiatives, estimates are aggregated, compared, and rolled up. They’re used to forecast timelines and support commitments at a system level. At that point, the assumptions behind them begin to weaken.

Different teams estimate differently. Context gets lost. Variability is hidden inside averages. What looked precise during planning becomes fragile during execution.

This is where Delivery Leads feel the tension most clearly.

Even with detailed estimates, reality keeps intervening. Work is interrupted. Dependencies emerge late. Priorities shift. Estimates are revised sometimes repeatedly. Over time, confidence in the numbers erodes.

To compensate, Delivery Leads often add buffers, contingency plans, or extra layers of reporting. These actions are meant to restore confidence, but they also increase complexity and pressure without addressing the root issue.

What’s missing in these situations isn’t better estimation. It’s evidence.

Evidence-based delivery starts by looking at how work has actually behaved in the past. Every delivery system produces data. Work items start and finish. Time passes. Some work flows smoothly. Other work slows down, waits, or gets blocked.

Over time, these patterns reveal far more about predictability than estimates ever can.

By observing cycle times, completion rates, and how work ages, Delivery Leads gain insight into how their system really operates. Variability becomes visible instead of hidden. Risk surfaces earlier, not only when deadlines are missed.

This shift changes delivery conversations.

Instead of debating whether an estimate was accurate, teams and leaders discuss patterns. Instead of asking who was wrong, they ask what the system is telling them. Instead of focusing only on planned outcomes, they consider likely outcomes.

Flow-based thinking builds on this evidence. It focuses on how work moves through the system over time. It highlights the impact of work in progress, handovers, and interruptions, and helps explain why starting more work often leads to finishing less.

Importantly, this approach doesn’t mean abandoning planning. Planning still matters. What changes is what informs it.

When planning is grounded in evidence rather than assumptions, Delivery Leads can speak more confidently about risk and likelihood. Stakeholders gain a clearer understanding of what’s possible. Teams feel less pressure to defend numbers and more space to focus on finishing work.

That’s why many Delivery Leads are exploring flow-based metrics as a complement to their existing practices, not to replace everything they do, but to strengthen decision-making where estimation falls short.

If this feels familiar, there’s a practical next step.

We’ve created The Delivery Leader’s Guide to Flow-Based Metrics, a practical introduction to leading delivery with flow, not points. The guide explores how Delivery Leaders can move from estimation to evidence, and use flow-based insights to improve predictability and confidence.

You can download the full guide to learn how to apply this shift in your own delivery context.