The false security of a spreadsheet

 

Spreadsheets are among the most powerful tools in modern organisations. They clarify plans. They align teams. They make trade-offs visible. They help leaders reason about complexity. But they also create one of the most dangerous illusions in product development: the illusion of certainty. 

A spreadsheet can make a plan look precise. It cannot make a plan true.

And yet many organisations quietly begin managing delivery as if precision equals certainty. That’s when they stop shipping products and start trying to ship assumptions. 

Why Spreadsheets Feel So Convincing

Spreadsheets translate ambiguity into structure:

• timelines become rows
• dependencies become columns
• confidence becomes percentages
• delivery becomes dates

The moment something is structured, it feels controllable.

This is psychologically powerful. Humans are wired to trust ordered representations of reality more than messy reality itself.

A spreadsheet doesn’t just organise work.

It organises belief.

The Shift From Planning Tool to Reality Substitute

Healthy teams use spreadsheets to support decisions.

Unhealthy teams begin using spreadsheets to replace decisions.

You can recognise the shift when conversations change from:

• What are we learning?

to:

• Are we still on track?

From:

• What changed? -> Why didn’t this match the forecast?
• Should we adjust direction? -> How do we defend the plan?

At that point, the spreadsheet stops describing reality and starts competing with it.

Reality always loses first. Eventually, the product does too.

Precision Is Not Predictability

Product development is not manufacturing.

You are not assembling known components into known outcomes. You are discovering:

• technical constraints
• usability gaps
• market misunderstandings
• integration surprises
• stakeholder misalignment
• incorrect assumptions about users

Most of these appear after work begins, not before.

A spreadsheet can represent known work well. It cannot represent unknown work honestly.

The more exploratory the problem, the more misleading detailed forecasting becomes.

Yet organisations often respond to uncertainty by increasing planning detail rather than increasing learning speed.

That’s how spreadsheets start replacing insight. 

How the Illusion Quietly Spreads Across an Organisation

The false security of a spreadsheet rarely appears suddenly. It accumulates gradually.

First:

roadmaps become commitments

Then:

commitments become expectations

Then:

expectations become performance signals

Eventually:

changing the plan becomes riskier than shipping the wrong thing

At that point, teams optimise for predictability instead of outcomes.

And predictability is not the goal of product development if you want to succeed. 

Progress is. Solving for customers is. 

When Oversight Becomes Theatre

Spreadsheets often become the backbone of reporting structures:

• status trackers
• delivery forecasts
• resource allocations
• portfolio summaries

Individually useful.

Collectively dangerous when they replace direct understanding.

Leaders begin trusting dashboards instead of conversations. Teams begin managing updates instead of solving problems. Risk becomes something to hide rather than something to surface.

You’ll recognise this pattern when:

• everything is “green” until suddenly it isn’t
• delivery slips appear late rather than early
• teams hesitate to revise timelines
• roadmap changes require escalation rather than evidence

The spreadsheet becomes a performance surface instead of a planning surface.

And performance surfaces reward stability over truth.

Why Organisations Prefer Spreadsheet Certainty

It’s not laziness. It’s risk management.

Spreadsheets provide:

• visibility for leadership
• alignment across teams
• defensibility in governance structures
• reassurance for stakeholders
• coordination across dependencies

They solve real organisational needs.

The problem starts when they’re asked to solve the wrong problem: eliminating uncertainty instead of navigating it.

Uncertainty isn’t a failure state in product development.

It’s the default state. 

The Hidden Cost of Spreadsheet-Driven Delivery

When spreadsheets become contracts instead of tools, several predictable effects appear.

• Teams stop updating assumptions because change looks like failure.
• Discovery work disappears from plans because it cannot be estimated precisely.
• Dependencies expand because alignment replaces ownership.
• Roadmaps stabilise while relevance declines.

Eventually, the organisation becomes very good at delivering what planned, and much worse at delivering what matters.

This is one of the most common failure modes in scaling product organisations.

The Difference Between Planning and Control

Planning supports learning. Control suppresses learning.

• A spreadsheet used well answers:
• What do we believe right now?
• A spreadsheet used poorly answers:
• What must remain true regardless of what we learn?

The first enables adaptation. The second prevents it.

What Strong Product Organisations Do Differently

They still use spreadsheets. Often extensively. But they treat them differently.

• They make assumptions explicit instead of hiding them inside timelines.
• They revisit plans frequently instead of defending them.
• They reward course correction instead of punishing deviation.

They separate:

• forecast confidence
• delivery progress
• problem understanding

Most importantly, they keep conversations closer to the people doing the work than to the documents describing the work.

Because reality lives in conversations.

Not cells.

A Practical Test for Your Own Organisation

Look at your roadmap spreadsheet and ask:

If new evidence contradicted half of this plan tomorrow, how quickly would we change it?

Immediately?
Next quarter?
Or never?

Your answer reveals whether the spreadsheet is guiding your organisation…

or governing it.