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In this article, we introduce the stthreg package of Stata commands to fit the threshold regression model, which is based on the first hitting time of a boundary by the sample path of a Wiener diffusion process and is well suited to applications involving time-to-event and survival data. The threshold regression model serves as an important alternative to the Cox proportional hazards model. The four commands that comprise this package for the threshold regression model are the model-fitting command stthreg, the postestimation command trhr for hazard-ratio calculation, the postestimation command trpredict for prediction, and the model diagnostics command sttrkm. These commands can also be used to implement an extended threshold regression model that accommodates applications where a cure rate exists.

Agriculture faces many challenges. Most importantly, it must produce more food, feed and other raw materials to satisfy the increasing and multiple demands of a growing population, which according to FAO and EU documents means an additional 70% more food globally for the projected 2.3 billion more people by 2050 (FAO, 2011; European Union, 2012). Thus, and not least, agriculture also has to contribute to sustainable economic prosperity and social well-being in rural areas, while protecting and enhancing natural resource capital such as soil, terrain, water and biodiversity, and the flow of ecosystem services, particularly the provision, regulatory and supporting service. The INSPIA approach tries to contribute to a more productive, resilient and resource efficient agriculture that delivers ecosystem services at the same time. Only the concomitant achievement of natural resource protection and the sustainable provision of more food, feed, non-food crops and more biodiversity and natural habitats – while also reducing greenhouse gas emissions -- can be considered as part of a holistically approach towards sustainable agricultural production intensification (Basch et al., 2011; Kassam et al., 2013). INSPIA will demonstrate sustainable agriculture through the implementation of a system of Best Management Practices (BMPs) and the measurement and monitoring of a set of defined indicators. INSPIA promotes sustainable practices that can sustainably protect and improve biodiversity, soils, terrain and water and contribute to ecosystems services required by society. When based on an integrated foundation of: (i) no or minimum soil disturbance; (ii) permanent soil mulch cover; and (iii) diversified cropping system, BMPs are capable of significantly ecologically enhancing and sustaining soil health, soil biodiversity and soil functions in agriculture production systems (www.inspia-europe.eu). The project covers over 50 farms in Belgium, Denmark, France and Spain and its main objectives are to: • Demonstrate that ecologically resilient BMPs can contribute to achieving sustainability in European agriculture. • Provide an index of farm sustainability based on a set of verifiable indicators. • Create a farm network that validates, demonstrates and communicates the BMPs. • Promote sustainable agricultural practices in different production systems. • Raise awareness among EU stakeholders.