Sparse Rank Regression for Restricted-Access Economic Data

Empirical research in economics increasingly relies on restricted-access data held by multiple firms or agencies, making it impossible to construct the estimator of interest on the pooled sample. At the same time, heavy-tailed distributions are pervasive in economics and finance outcomes such as prices, expenditures and loan sizes. We study sparse, robust estimation in the restricted-access setting. The infeasible pooled benchmark is convoluted rank regression (CRR), a smooth rank-based estimator designed for heavy-tailed outcomes. Because the CRR criterion is a non-additive U-statistic, existing communication-efficient methods built for additive empirical losses do not directly apply. We propose distributed convoluted rank regression (DCRR), a surrogate criterion built from a single local CRR loss and an aggregated gradient correction, and show that it shares the same population minimizer as the pooled CRR objective. Building on this surrogate, we develop a two-stage sparse procedure: an iterative $l_1$- penalized stage followed by a folded-concave refinement. For the resulting estimator, we establish non-asymptotic error bounds, a distributed strong oracle property, and a distributed criterion for consistent model selection. Simulations and an application to used-car prices show that DCRR closely approximates pooled CRR and improves on naive divide-and-conquer, particularly under heavy-tailed errors.