Premium Development Triangles

This dataset provides a comprehensive view of earned premium development by accident or underwriting year and development period, segmented by exposure base, line of business, and region. It is designed for actuarial analysis, rate adequacy studies, and combined ratio calculations, enabling insurers to track premium trends and performance over time.

  • last updated 2 Nov 2025
  • by GoMask
The brief that made it

Exposure base trending and premium development analysis

Sample rows

preview · 8 of 500 rows · all 11 columns
idintegerdata_sourcestringdevelopment_periodintegerregionstringyear_typestringyearintegerexposure_basestringpremium_amountfloatcurrencystringline_of_businessstringas_of_datedate
1CoreSys12United Statesaccident2021written_premium245678.55USDauto2022-05-15
2DataMart48Western Europeunderwriting1995earned_premium138000.1EURproperty1998-03-01
3CoreSys18Californiaaccident2007policy_count950USDhealth2008-10-17
4FutureSys120Space Colonyunderwriting2095policy_count375CNYaviation2096-02-23
5NextGen24Canadaaccident2015earned_premium296000.8CADproperty2016-04-04
6LegacyDB36Midwest USaccident1985written_premium172500USDauto1987-09-25
7CoreSys6North Americaunderwriting2023written_premium452300.2USDauto2024-01-11
8WebPortal12Onlineaccident2002policy_count1800USDpet2003-02-20

What the 500 rows show

from the 500-row sample

Archive (data source) stands out: mean development_period is 113.4, against 34.4 for the rest.

  • 24median development_period
  • 2year types
  • 4exposure bases
  • 11line of businesses
  • 12currencies
  • 122,666median premium_amount
Mean development_period by data_source500 rows
010020016.2Core…164 r…12.7WebP…68 ro…95.3Futu…65 ro…60.4Lega…65 ro…28.9Data…62 ro…113.4Arch…42 ro…9.8Next…34 ro…
development_period500 rows, in bands of 20
011523023011936140101060120development_period →

Median 24, from 0 to 120.

region500 rows · top 10 of 21 values
  1. United States69
  2. North America50
  3. Western Europe48
  4. Global32
  5. Online31
  6. California30
  7. Switzerland30
  8. United Kingdom27
  9. Singapore27
  10. Midwest US21
11 columns by typefrom the column list below
  • string 6
  • integer 3
  • float 1
  • date 1

Columns

11 columns in three groups
blueprint · 11 columns
columntypedescriptionexample
Text 6 columns
year_typestringType of year used for grouping premium (e.g., accident year or underwriting year)accident · underwritingaccident
exposure_basestringType of exposure base used for trending (e.g., written premium, earned premium, policy count)written_premium · earned_premium · policy_count · otherwritten_premium
currencystringCurrency code for the premium amount (ISO 4217 format, e.g., USD, EUR)12 currencies · optionalUSD
line_of_businessstringInsurance line of business associated with the premium record (e.g., auto, property, liability)11 businesses · optionalauto
regionstringGeographic region or market segment for the premium recordoptionalUnited States
data_sourcestringSource system or dataset from which the premium record was derived7 sources · optionalCoreSys
Numbers 4 columns
idintegerUnique identifier for each premium triangle recordunique · 1 or more1
yearintegerThe accident or underwriting year for the premium record1,900 to 2,1002021
development_periodintegerNumber of months or years since the start of the accident/underwriting year (e.g., 12, 24, 36)0 to 12012
premium_amountfloatAmount of earned premium for the given year and development period0 or more245678.55
Dates and times 1 column
as_of_datedateDate the premium data was last updated or extractedoptional2022-05-15

Use it for

  • median develop…24500 rowsmean development peri…16.2Core…12.7WebP…95.3Futu…60.4Lega…

    An insurance dashboard

    Development_period by data_source and a breakdown of region. Excel, Power BI or Tableau.

  • Why do the 42 Archive rows have a mean development_period of 113.4?

    A root-cause class exercise

    Hand out the rows and one question. The answer is in the data, not in the brief.

  • A software demo

    Believable rows with year_type, year and development_period to fill a screen in front of a buyer.

Not quite right?

Make it yours.

Same 11 columns, your size and your rules. See 20 rows before you pay.

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This dataset500 rows11 columns
Yours10,000 rows11 columnsregion: UK only

blueprint · premium-development-triangles

Behind this dataset

Same schema. As many rows as you need.

These 500 rows came out of a blueprint — 11 columns with generation rules behind each one. Open it in Data Factory to retune a column, add your own, wire in foreign keys, and run it at the size you actually need.

Rules it was built with
  • Earned premium recognized over policy period
  • Accident year premium for loss ratio calculations
  • Underwriting/policy year premium alternative view
  • Premium development due to audits and endorsements
  • Ultimate earned premium after all adjustments
  • Loss ratio = Incurred losses / Earned premium
  • Rate level changes tracked by effective date
  • On-level premium adjustments for rate changes
Rows
Open the blueprint in Data Factory

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Exports
CSV, JSON, JSONL, Parquet, SQL, Excel, TSV, XML
Licence
yours to use, including commercially
API slug
premium-development-triangles

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