Driver Scenario Interactions

This article explains how drivers interact with scenarios in Model Reef.

You will learn:

• How drivers are stored and copied across scenarios.

• How to structure scenario specific driver assumptions.

• Patterns for base, downside and upside cases.

• How driver choices flow through to statements and valuation.

Each scenario in Model Reef is a separate model, with its own drivers, variables and Data Library entries.

1. Drivers are scenario specific

When you duplicate a model to create a scenario:

• All drivers in the Data Library are copied into the new scenario.

• The copied drivers can be edited independently.

• Changes to drivers in one scenario do not affect any other scenario.

This means:

• Base Case, Downside and Upside each have their own driver paths.

• You can freely experiment with assumptions in one scenario without risk.

2. Structuring driver sets for scenarios

A clean pattern is to follow these steps:

1

Design a base driver set

Design a base driver set in your first model, with clear names and notes.

2

Duplicate the model per scenario

Duplicate the model for each scenario you want, for example Base, Downside, Upside.

3

Change only driver series per scenario

Change only the driver series in each scenario to reflect different assumptions.

4

Keep formulas and variable structures consistent

Leave formulas and variable structures the same so comparisons are apples to apples.

You do not need to create separate driver names for each scenario if the models are duplicated. The scenario context itself makes them distinct.

3. Types of scenario interactions

Common ways drivers differ between scenarios include:

• Level changes

  • Different starting points for volumes, prices or costs.

• Path changes

  • Different growth rates, inflection points or recovery shapes.

  • Different timing of step changes or shocks.

• Mix changes

  • Different product, channel or geography mix.

  • Different allocation of spend across marketing channels or teams.

Each of these can be expressed purely via driver series.

4. Drivers and valuation scenarios

Valuation scenarios often use driver changes in combination with:

• Different discount rates.

• Different terminal value assumptions.

• Different capex or working capital patterns.

For example:

• A conservative scenario uses lower revenue growth drivers and higher discount rates.

• An aggressive scenario uses higher growth drivers and more optimistic margin or capex patterns.

Because valuations derive from free cashflows, which derive from variables driven by drivers, the effect of driver changes is visible end to end.

5. Reporting and comparing driver based scenarios

Once you have separate scenario models with different drivers, you can compare them by:

• Viewing P&L, Balance Sheet, Cashflow and Cash Waterfall for each scenario.

• Comparing valuation metrics such as NPV and IRR.

• Building dashboards or reports that place scenarios side by side.

• Exporting or presenting scenario specific charts and KPIs.

The underlying driver differences remain inside each scenario model, but their effects are visible throughout the outputs.

6. Good practice for scenario driver design

Guidelines:

• Keep driver names the same across scenarios where structure is the same.

  • This makes it easy to know which assumption you are changing.

• Use notes to document what differs in each scenario.

• Avoid changing formulas between scenarios unless you are modelling a structural change.

• Use modifier drivers for scenario overlays when you want to keep base drivers unchanged.

Clear scenario design makes it easy to explain not just what changes between scenarios, but why.

Related articles

• Multi-Product SaaS P&L

• Operations & Unit Economics

• Driver Overview

• Scenario Selector