Combine Multiple External Data Sources

This guide explains how to combine multiple external data sources inside a single Model Reef model using the Data Library as the integration layer. Typical sources include PDFs, Excel or CSV files, accounting systems and stock ticker fundamentals.

The aim is to use the model as a single, consistent view of the business, even when inputs come from many different systems.

Before you start

You should have:

• A clear list of data sources you want to combine, for example:

  • Historicals from Xero or QuickBooks.

  • Forecasts or snapshots from PDFs or Excel models.

  • Operational or driver data from CSV exports.

  • Market data from stock tickers or APIs.

• A sense of which source should be treated as authoritative for each metric.

If you are new to imports, read:

• PDF Import Overview

• Xero Integration

• QuickBooks Integration

• Stock Ticker import

What you will build

By the end of this guide you will have:

• A model where multiple data sources feed the Data Library.

• Variables that use the Data Library to generate consistent financial statements.

• A structure that reduces duplication and clarifies which source is authoritative for each assumption.

1

Decide which model will host the combined data

Start by selecting or creating a primary model that will host your integrated view, for example:

• Company - Consolidated Data Model.

Ensure that:

• Periodicity and currency settings match the dominant or most important source.

• Model start and end dates cover all relevant data.

This is the model you will connect all sources to.

2

Use the Data Library as the integration hub

The Data Library is the central place where all imported series live. Each entry can:

• Record its origin (for example Xero, PDF, CSV, ticker).

• Be tagged and named consistently.

• Be re used by multiple variables across branches.

Before importing anything, decide on naming conventions and tags, for example:

• SRC Xero versus SRC PDF versus SRC CSV or SRC Ticker as tags.

• Clear names like Revenue - Online - Actuals, Revenue - Online - Forecast, Driver - FX - EUR to GBP.

This keeps the integration layer readable and maintainable.

3

Import accounting actuals (Xero or QuickBooks)

If you use an accounting system:

• Connect Model Reef to Xero or QuickBooks.

• Import and map the Chart of Accounts.

• Import historical actuals for the desired period.

• Confirm that the imported series appear in the Data Library with appropriate names and tags.

These series become your authoritative record of historical financial performance.

4

Import additional historical or forecast data from PDFs and Excel

If you have PDFs or Excel files with:

• More detailed historical breakdowns.

• Management forecasts or scenarios.

• Operational driver tables.

Import them into the same model using PDF or Excel imports.

During mapping:

• Decide whether each series supplements or overlaps with accounting data.

• Use names and tags to show whether a line represents:

  • An adjusted view of history.

  • A separate forecast or scenario.

  • A driver that does not exist in the ledger.

Avoid overwriting accounting actuals unless there is a deliberate reason to align with a restated view.

5

Import operational or driver data via CSV

For non-accounting metrics, such as:

• Customer counts.

• Volumes.

• Pricing.

• FX rates.

Import CSV files into the Data Library:

• Map each column to a Data Library entry with clear names.

• Set frequency and units correctly.

• Tag them as operational drivers, for example Driver - Units - Retail, Driver - FX - USD to GBP.

These series can drive revenue, cost or other variables without appearing directly on financial statements.

6

Import market or external fundamentals if needed

If you incorporate external market data, such as:

• Peer fundamentals via stock ticker.

• Index or macro series from APIs.

Import these into the Data Library and tag them, for example SRC Ticker, SRC Macro. Use them in formulas or drivers as needed, keeping the origin clear.

7

Build variables that reference the correct sources

With multiple sources in the Data Library, be explicit about which you use in variables.

Examples:

• History plus forecast:

  • Historical periods use series imported from Xero.

  • Forecast periods use management forecast or driver based series.

• Adjusted history:

  • Use management adjusted series for certain P&L lines where accounting history is not representative.

• Mixed drivers:

  • Use CSV based unit drivers and accounting based price realisation data to build revenue.

Document your choice of authoritative sources in notes so that the logic is clear to future users.

8

Validate statements and reconcile across sources

Once variables are built:

• Review P&L, Balance Sheet, Cashflow and Cash Waterfall.

• Compare key figures to:

  • Accounting reports.

  • Management forecasts.

  • External reference points.

Where numbers do not align, verify that:

• The correct source was referenced in the variable.

• Duplicate series are not being double counted.

Tighten mapping and variable design until the combined view is consistent.

Check your work

• Data Library entries clearly show source, purpose and units.

• Each variable uses the intended Data Library series.

• Financial statements reconcile with authoritative reference reports.

• It is clear how to add or update data from each source in future.

Troubleshooting

Conflicting values from different sources

Choose and document a priority order, for example accounting actuals first, management adjustments second, external series third, and implement variables accordingly.

Data Library becomes cluttered

Introduce a naming and tagging convention and periodically archive or de-emphasise obsolete series.

Hard to trace where a particular line comes from

Use notes and tags to indicate the source and intended role of each series and variable, and add brief documentation in your GitBook workspace.

Related guides

• Media, Agencies & Creative Studios

• Fundamental Data Mapping

• Importing & Data Inputs

• Formula Editor Layout