Connected Models & Modular Design
Connected Models let you build more sophisticated ROI Models and Calculators from multiple calculation models rather than requiring every calculation to exist within one large model.
This can help you create a more modular modelling structure, where different parts of the business case are maintained separately but work together as part of the overall calculation experience.
What is a Connected Model?
A Connected Model is another calculation model that contributes values or calculations to the model you are building.
Instead of placing every assumption, formula and result inside a single Calculator, you can connect supporting models and use their values as part of the wider business case.
For example, a larger ROI Model might contain separate calculation models for:
Productivity benefits
Labour savings
Revenue impact
Implementation costs
Ongoing technology costs
Risk reduction
Those models can then contribute to a wider model that brings the results together.
Why use modular models?
You do not need Connected Models for every business case.
For smaller Calculators, keeping the calculation logic within a single model will often be simpler.
Connected Models become more useful when the business case contains calculations that are:
Substantial enough to manage independently
Reused across different models
Owned or maintained separately
Easier to understand when divided into logical calculation areas
Part of a larger financial model with several distinct value drivers
A modular structure can make complex models easier to build, maintain and explain.
A simple example
Imagine you are building an ROI Model for a large automation programme.
The overall business case might contain:
Productivity Model Calculates employee hours released and the resulting labour value.
Revenue Model Calculates additional revenue created through improved conversion or capacity.
Technology Cost Model Calculates implementation and recurring technology costs.
These supporting models can contribute to the main business case rather than requiring all three calculation structures to be recreated inside one Calculator.
The overall model can then combine their outputs into measures such as:
Gross Benefit → Total Cost → Net Benefit → ROI → Payback
Connecting models
Connected Models are configured within the model-building experience.
When creating a modular model, identify the supporting model you want to connect and configure the values that need to pass between the models.
The exact relationship will depend on the business case.
For example, one supporting model might provide:
Annual Productivity Benefit
while another provides:
Annual Technology Cost
The main model can then use those values within its wider financial calculations.
Tip: Connect models around meaningful calculation boundaries. Avoid splitting a simple calculation across several models simply because the capability is available.
Values can flow between models
A connected model can provide values that are used by another part of the business case.
This makes it possible to maintain a calculation in one model while allowing its result to contribute to a wider ROI calculation.
When the underlying values change, dependent calculations can update as part of the model experience.
This allows modular models to behave as one connected business case rather than as a collection of unrelated calculations.
Design models around business concepts
A useful way to decide where one model should end and another should begin is to think about the business logic rather than the number of formulas.
Good candidates for separate models might include:
Workforce productivity
Operational cost savings
Revenue improvement
Infrastructure savings
Risk or loss avoidance
Implementation costs
Subscription or licence costs
Each model should represent a calculation area that makes sense independently.
The objective is:
Clear calculation responsibility → understandable connection → coherent overall business case
Avoid unnecessary fragmentation
Modular design can make complex models easier to manage, but creating too many small models can have the opposite effect.
Avoid creating a separate Connected Model for every individual KPI or intermediate calculation.
If several calculations naturally belong together and are easier to understand as one model, keep them together.
Use Connected Models when separating the calculation creates a meaningful modelling boundary.
What recipients experience
Connected Models can also help make a complex business case more transparent to the people using your published model.
When supporting model information is available, the ROI Viewer can provide:
How this model is built
This allows recipients to understand that the business case is supported by connected calculation models rather than presenting the overall result as an unexplained number.
Depending on how the model has been configured, recipients may be able to:
See the supporting models involved
Review information about those models
Understand how different modelling areas contribute to the wider business case
View a visual representation of the model relationships
Open a supporting model where that experience is available
This gives recipients additional context without requiring the full modelling structure to be displayed permanently within the main ROI experience.
Connected Models and Calculation Lineage
Connected Models explain how the wider model is structured.
Calculation Lineage answers a different question:
How was this particular result calculated?
For example:
How this model is built might show that the overall ROI uses a Productivity Model and a Technology Cost Model.
Trace the numbers can help the recipient explore how a particular calculated figure was derived.
Used together, these capabilities can make complex business cases considerably easier to understand and validate.
Updating Connected Models
When working with modular calculations, consider the effect of changes across the connected model structure.
If you change:
An Input
An Output
A Formula
A model reference
A value used by another model
review the models that depend on that information.
Preview the complete experience after significant changes to confirm that the wider calculation still behaves as expected.
Best practices
When designing modular ROI Models and Calculators:
Keep simple models simple.
Separate calculations only where there is a clear business or modelling boundary.
Give supporting models clear, descriptive names.
Make the purpose of each model understandable.
Keep relationships between models as simple as the business case allows.
Review connected calculations after changing an underlying model.
Preview the complete recipient experience before publishing.
Use Calculation Lineage where appropriate to help recipients understand the figures produced by the model.
The key principle
Connected Models are not about making an ROI Model more technically complex.
They are about making sophisticated business cases easier to structure.
A useful modular design should make it clearer:
What each model calculates → How the models connect → How they contribute to the final business case
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