Does this skill handle person-to-household aggregation?

Yes, PolicyEngine's aggregation patterns automatically handle summing values from lower-level entities (like Person) to higher-level entities (like Household or Tax Unit) without manual loops.

Can I use parameter lists to define what variables to sum?

Absolutely. Both 'adds' and 'add()' support referencing parameter tree paths that contain lists of variable names, making the model more maintainable and configurable.

When should I use 'adds' instead of the 'add()' function?

Use the 'adds' attribute when a variable is strictly a sum of other variables with no additional logic. Use the 'add()' function inside a formula when you need to apply conditions, limits like max_(), or additional mathematical operations.

Why is manual summing considered an anti-pattern in PolicyEngine?

Manual summing via entity members is less efficient and more error-prone. Using built-in aggregation patterns ensures that PolicyEngine's internal engine optimizes the calculation and correctly handles entity relationships.

PolicyEngine Aggregation Patterns

Name: PolicyEngine Aggregation Patterns
Author: PolicyEngine

byPolicyEngine

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数据科学与机器学习

Implements standardized patterns for summing tax and benefit variables across entities using the adds attribute and add() function.

关于

This skill provides Claude with domain-specific knowledge for PolicyEngine development, focusing on the critical task of variable aggregation. It establishes a clear decision framework for choosing between the declarative 'adds' attribute for simple sums and the more flexible 'add()' function for complex logic involving conditions or limits. By following these patterns, developers can ensure that variables are correctly summed across different entity hierarchies—such as Person to Household or Tax Unit—while avoiding common anti-patterns like manual iteration or redundant formulas.

主要功能

Anti-pattern detection to prevent manual summing errors
2 GitHub stars
Automatic cross-entity aggregation (Person to Household/Tax Unit)
Parameter-driven variable list integration
Declarative 'adds' attribute implementation for zero-logic sums
Advanced 'add()' function guidance for conditional aggregation

使用场景

Summing multiple income sources into a single gross income variable
Aggregating household benefits across different simulation units
Counting eligible individuals within a unit using boolean summation

关于

主要功能

Anti-pattern detection to prevent manual summing errors
2 GitHub stars
Automatic cross-entity aggregation (Person to Household/Tax Unit)
Parameter-driven variable list integration
Declarative 'adds' attribute implementation for zero-logic sums
Advanced 'add()' function guidance for conditional aggregation

使用场景

Summing multiple income sources into a single gross income variable
Aggregating household benefits across different simulation units
Counting eligible individuals within a unit using boolean summation