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%matplotlib inline

Basic Triangle Creation

This example demonstrates the typical way you'd ingest data into a Triangle. Data in tabular form in a pandas DataFrame is required. At a minimum, columns specifying origin and development, and a value must be present. Note, you can include more than one column as a list as well as any number of indices for creating triangle subgroups.

In this example, we create a triangle object with triangles for each company in the CAS Loss Reserve Database for Workers' Compensation.



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import chainladder as cl
import pandas as pd
import seaborn as sns
import matplotlib.pyplot as plt

# Read in the data
lobs = 'wkcomp'
data = pd.read_csv(r'https://www.casact.org/research/reserve_data/wkcomp_pos.csv')
data = data[data['DevelopmentYear']<=1997]

# Create a triangle
triangle = cl.Triangle(
    data, origin='AccidentYear', development='DevelopmentYear',
    index=['GRNAME'], columns=['IncurLoss_D','CumPaidLoss_D','EarnedPremDIR_D'])

# Output
print('Raw data:')
print(data.head())
print()
print('Triangle summary:')
print(triangle)
print()
print('Aggregate Paid Triangle:')
print(triangle['CumPaidLoss_D'].sum())

# Plot data
ax = triangle['CumPaidLoss_D'].sum().T.plot(
    marker='.', title='CAS Loss Reserve Database: Workers Compensation');
ax.set(xlabel='Development Period', ylabel='Cumulative Paid Loss')

plt.show()