摘要：This study investigates the factors that impact the duration of trade relationships in U.S. fresh fruit and vegetable imports. We employ both the survival analysis (KM estimates and Cox PH model) as well as a count data model. The preliminary results indicate that SPS treatment requirements positively impact duration while new market access issued during the study period negatively impacts duration. Developed countries and countries located in North America experience longer duration. Other factors typically included in trade duration models were also investigated. Additionally, we employ a Heckman two-step procedure to understand the impact of duration on the probability of trading and trade volume, and find that both are positively impacted therefore suggesting that more stable trade relationships also tend to involve a higher volume of trade.
关键词：Fresh fruits and vegetable;U;S; imports;Survival Analysis;Count Data;Heckman Two-Step Model
