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On this page

  • 1 Where it fits
  • 2 Python API
  • 3 Minimal example
  • 4 summary() contract

MatrixCompletion

Nuclear-norm panel counterfactual completion

from _api_doc_utils import *

1 Where it fits

Group: Causal inference

MatrixCompletion treats untreated cells as observed entries and treated cells as missing counterfactuals. It estimates a low-rank untreated-outcome surface, optionally with unit and time effects, using nuclear-norm style shrinkage.

The completed values in treated cells become counterfactual outcomes for ATT and event-study summaries.

2 Python API

Constructor: cm.MatrixCompletion

Call MatrixCompletion(...).fit(y, w). predict() returns completed/counterfactual values and summary() reports ATT, completed matrices, treatment effects, low-rank components, singular values, objective history, and panel summaries.

print(inspect.signature(cm.MatrixCompletion))
(lambda_l=None, lambda_fraction=0.25, fit_unit_effects=True, fit_time_effects=True, max_iterations=500, effect_iterations=2, tolerance=1e-06, svd_method=Ellipsis, svd_rank=None, svd_oversamples=10, svd_power_iter=1, svd_seed=None)
cls = cm.MatrixCompletion
display(HTML(html_table(["Public method"], public_methods(cls))))
Public method
fit(self, /, y, w)
predict(self, /)
summary(self, /)

3 Minimal example

rng=np.random.default_rng(18)
load=rng.normal(size=(10,2)); fac=rng.normal(size=(2,14)); y=load@fac+rng.normal(scale=.1,size=(10,14)); w=np.zeros_like(y); w[7:,9:]=1; y[7:,9:]+=1
model=cm.MatrixCompletion(max_iterations=100, tolerance=1e-5); model.fit(y,w)
print(model.summary()["att"])
print(model.predict().shape)
1.201613382954045
(10, 14)

4 summary() contract

The table below is generated by fitting the live class in this repository and then inspecting summary(). Shapes are shown because most values are plain NumPy arrays or scalars.

rng=np.random.default_rng(118); y=rng.normal(size=(8,10)); w=np.zeros_like(y); w[6:,7:]=1; y[6:,7:]+=.8
model=cm.MatrixCompletion(max_iterations=80,tolerance=1e-5); model.fit(y,w)
summary = model.summary()
display(HTML(html_table(["summary() key", "shape"], summary_shape_rows(summary))))
summary() key shape
completed (8, 10)
low_rank (8, 10)
unit_effects (8,)
time_effects (10,)
singular_values (8,)
lambda_l ()
objective ()
iterations ()
history_objective (16,)
history_rmse (16,)
svd_method ()
svd_rank ()
svd_oversamples ()
svd_power_iter ()
att ()
counterfactual (8, 10)
treatment_effect (8, 10)
event_study ()
group_means ()
control_units (6,)
treated_units (2,)
cohorts (1,)