Sequential Threshold-Spatial-Quantile Panel Estimation R package tsqr version 0.2.0 Implements a sequential panel estimation protocol for regional economic panels that combines three estimation layers in a fixed order. The first layer applies a two-way fixed effects baseline. The second layer applies the panel threshold regression method of Hansen (1999) <doi:10.1016/S0304-4076(99)00025-1> to identify structural breaks at an unknown threshold of a moderating variable, with bootstrap inference following Hansen (2000) <doi:10.1111/1468-0262.00124>. The third layer applies a spatial Durbin model with an impact decomposition following LeSage and Pace (2009, ISBN:978-1-4200-6424-7) to quantify direct and indirect spillover effects. The fourth layer applies the two-step panel quantile estimator of Canay (2011) <doi:10.1111/j.1368-423X.2011.00349.x> to document distributional heterogeneity in the outcome. The threshold identified in the second layer defines a subsample used as structured input to the fourth layer, and a consistency check evaluates whether the three sets of results are jointly compatible with a common underlying structural relationship. An illustrative panel of 33 districts of the state of Maharashtra, India, observed over 10 agricultural years, is included with the package. Software Depends: R (>= 4.1.0) Imports: plm (>= 2.6-0), spdep (>= 1.2-0), spatialreg (>= 1.2-0), quantreg (>= 5.90), ggplot2 (>= 3.4.0), stats, utils Suggests: testthat (>= 3.0.0) Prakash Vhankade <prakash.vhankade@gipe.ac.in> Comprehensive R Archive Network (CRAN) Prakash Vhankade [aut, cre] (ORCID: <https://orcid.org/0009-0005-2436-0603>) GPL-3 2026-07-06 application/tgz https://CRAN.R-project.org/package=tsqr doi:10.32614/CRAN.package.tsqr