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Getting Started

March 14th, 2026 · The IBNR.net Team

Welcome to IBNR.net! This guide will walk you through the essential steps to begin using the platform for IBNR reserve estimation.

Triangle Data#

The loss development method begins with triangle data. There are three main options to load triangle data:

  1. Upload Triangle Data: If you already have triangle data prepared, upload these files directly.
  2. Upload Columnar Data: Import columnar data files to the platform. After upload, the platform will provide options to convert the data into a triangle format, allowing the user to filter on one or many fields for multiple triangle uploads. Triangle cells can be traced back to the original source data, allowing for efficient analysis and outlier detection. Uploading columnar data is only available on the Pro, Team, or Enterprise tiers.
  3. Generate a Synthetic Triangle: The platform can generate a synthetic development triangle from scratch, allowing you to experiment and learn the workflow without using real data.

Quick Start Guide#

Follow these steps to generate your first IBNR estimate:

Step 1: Upload Your Data#

  1. Sign in and go to the Manage Data page
  2. Drag and drop your file, click to browse, or paste data directly
  3. The system automatically detects your data format (triangle or columnar)

After uploading, you’ll see a dialog showing the detected properties.

  • If triangle data is detected, you’ll be prompted to review the detected properties and save the triangle group.
  • If your data is in columnar format, you’ll be prompted to access the Columns to Triangles tool after upload.

Step 2: Select Your Triangle Group#

Go to the My Triangles page to review your uploaded triangle groups. Select a triangle to load it for analysis. Your active triangle will then appear in the dropdown menu at the top right of the screen.

Step 3: Run Your Analysis#

Once a triangle or triangle group is selected, navigate to any of the tabs in the sidebar to begin analysis:

Data

  1. Properties - Check dimensions, date ranges, and periodicity of your triangle
  2. Checks - Validate data completeness and consistency
  3. Membership - Upload or edit member counts by period

Adjustments

  1. Triangle Adjustments - Remove rows, apply filters, or make manual cell-level changes
  2. Average Methods - Select and compare actuarial averaging methods for development factors
  3. Seasonality Factors - Upload, choose from presets, or derive monthly seasonality factors
  4. Projection Method - Configure base/projection periods and credibility weights
  5. Margin - Apply a margin percentage to your reserve estimates

Exhibits

  1. Spreadsheet - View and export your analysis in a grid-based layout
  2. Summary Exhibits - View lag/cumulative triangles, development factors, completion factors, and IBNR reserves

All changes are documented in the team notifications page, allowing you to track your analysis. For Team and Enterprise tiers, changes are saved at the user level, allowing for further collaboration and traceability.

A typical reserving workflow might look like this:

Upload Data → Validate Data Integrity
     ↓
Review Lag Triangle → Adjust for Outliers
     ↓
Validate Age-to-Age Factors → Select a Reasonable Average Method
     ↓
Credibility Adjustments → Apply the Bornhuetter-Ferguson Method (if needed)
     ↓
Risk Assessment → Validate IBNR Estimate → Apply Margin (if needed)
     ↓
Reporting → Generate Report → Review and Share

Step 4: Generate a Report#

For Pro tiers and above, each relevant page will also allow you write or generate notes for a professional report. Notes are automatically imported to the report.

Navigate to the Report page to view the report.

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