Estimating Level of Effort: It’s an Art, Not an Exact Science

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One of the most common asks I get as a Solution Architect is to estimate the level of effort (LOE) for a ServiceNow implementation. Usually, this comes right after the scope has been defined—or at least narrowed down enough to start thinking about what it’ll take to get the work done.

In most cases, we lean on some kind of estimator tool. You might hear it called a sizing tool, a scoping calculator, or just “the effort sheet.” I’ve seen a few different versions over the years, and they’re usually built from historical data, adjusted for complexity and contingencies. Whether it’s a web-based tool or a good old Excel file, it needs to be reviewed and updated regularly to stay relevant.

The challenge is that effort is subjective. What one person sees as a quick win, another might see as a multi-week task. Even defining what counts as a standalone component can vary. That’s why building or updating an estimator should be a team effort. You need consensus on how capabilities are broken down and how much time each one typically takes—whether you’re measuring in hours or person-days.

Most estimators include effort for things like requirements gathering, documentation, testing, and release readiness. Some even factor in the level of client involvement—ranging from turnkey delivery to full-on white-glove support. And yes, I’ve seen estimators that scale based on how much “handholding” the client might need.

Of course, not everything fits neatly into a tool. Sometimes you’re estimating work that’s highly custom or just too advanced for the standard model. That’s when experience kicks in. You’ll need to draw from past projects—yours and your team’s—and build an estimate that’s not only reasonable but defensible. Stakeholders will ask questions, and you need to be ready to explain how you got to your numbers.

When I’m building custom estimates, I like to offer two or three options. It opens the door for discussion and negotiation. And let’s be honest—there’s always some trade-off involved. You need to know your limits and what you’re willing to flex on.

At the end of the day, remember: it’s an estimate, not a guarantee. I often remind folks that “perfection is the enemy of progress.” The goal is to provide a thoughtful, informed starting point—not a flawless prediction.

Estimating LOE is part science, part intuition, and part collaboration. Use tools, lean on your team, and stay flexible. What’s your approach to estimating effort in ServiceNow projects? Let’s swap stories and tips in the comments.