formative-ds 2.0.0

A Python library for quantitative reasoning.

formative

Python library for quantitative reasoning.

Requirements

• Python 3.10+

Installation

pip install formative-ds

Docs

Comprehensive documentation is available at docs.getformative.dev.

Usage

Causal estimation

from formative.causal import DAG, OLSObservational

dag = DAG()
dag.assume("ability").causes("education", "income")
dag.assume("education").causes("income")

result = OLSObservational(
    dag,
    treatment="education",
    outcome="income"
).fit(df)

print(result.summary())

Confounders declared in the DAG are controlled for automatically. If a confounder is absent from the dataframe, an IdentificationError is raised before any estimation runs.

Decision rules

from formative.game import maximin, maximax, hurwicz, laplace, minimax

outcomes = {
    "stocks": {"recession": -20, "stagnation":  5, "growth": 30},
    "bonds":  {"recession":   5, "stagnation":  5, "growth":  7},
    "cash":   {"recession":   2, "stagnation":  2, "growth":  2},
}

maximin(outcomes).solve()        # safest choice (best worst case)
maximax(outcomes).solve()        # most optimistic (best best case)
hurwicz(outcomes, alpha=0.5).solve()  # blend of optimism and pessimism
laplace(outcomes).solve()        # highest average payoff
minimax(outcomes).solve()        # lowest worst-case regret

See online documentation at docs.getformative.dev for more examples and details.

Local development

Requires uv.

git clone https://github.com/maxpagels/formative
cd formative
uv sync --dev

This creates a .venv, installs all dependencies, and installs the package in editable mode.

Releasing a new version

uvx bump-my-version bump patch   # 0.1.0 → 0.1.1 (bug fixes)
uvx bump-my-version bump minor   # 0.1.0 → 0.2.0 (new features)
uvx bump-my-version bump major   # 0.1.0 → 1.0.0 (breaking changes)
git push --follow-tags            # triggers publish to PyPI

Running tests

uv run pytest

Importing without installing

To use formative from a script outside this repo without installing it, either prepend the path at runtime:

import sys
sys.path.insert(0, "/path/to/formative")

from formative.causal import DAG, OLSObservational

Or set PYTHONPATH before running:

PYTHONPATH=/path/to/formative python your_script.py