The Paris Agreement, the Sustainable Development Goals, the Sendai Framework and the New Urban Agenda share a vision of global sustainable development, with several overlapping goals and targets. However, these agendas are often treated along sectoral boundaries leading to highly branched implementation. Underusing potential synergies is not only a burden for governments due to the costs of redundancies and inefficiency but can also hinder collective goals and lead to inter-agenda trade-offs. Despite growing attention on policy coherence in research and policy, existing literature fails to explain why it is so hard to achieve despite widespread recognition of its theoretical value. Based on a literature review and fieldwork in Mexico, our research focuses on the perception of the people in charge of operationalizing the agendas. We develop a typology of non-monetary costs and benefits that encompasses the alternative scenarios of 1) increased coherence in the implementation of the agendas in Mexico and 2) a business-as-usual scenario. Results challenge the dominant approach that focuses on binary policy coherence/incoherence analysis, by identifying also perceived benefits of incoherence and costs of building coherence. They also highlight the importance of often overlooked barriers to cross-sectoral and cross-scalar collaboration driven by institutional arrangements and work culture. The resulting typology differentiates drivers and manifestations of (in)coherence from their impacts on institutions and society. From this, we derive that a scenario of increased coherence in the implementation of the Post-2015 Agenda represents net gains to society and only relative losses to institutions, once the current costs of incoherence are discounted. However, the process of building policy coherence is beyond easy fixes, requiring structural change. Otherwise, institutions risk falling into a cosmetic level of coherence that is both costly and ineffective.

《巴黎协定》，《可持续发展目标》，《仙台框架》和《新城市议程》对全球可持续发展抱有共同愿景，并有多个重叠的目标和指标。但是，这些议程通常是沿部门界限对待的，从而导致高度分支的实施。充分利用潜在的协同增效不仅是由于冗余和低效率的代价给政府带来的负担，而且还可能阻碍集体目标并导致议程间的权衡。尽管人们越来越关注研究和政策中的政策连贯性，但现有文献未能解释为何尽管其理论价值得到广泛认可，却很难实现。根据墨西哥的文献综述和实地考察，我们的研究重点放在负责执行议程的人员的看法上。我们开发了一种非货币成本和收益的类型，其中包括以下备选方案：1）在墨西哥执行议程的过程中提高一致性，以及2）一切照旧。结果还通过识别不连贯的收益和建立连贯性的成本，挑战了专注于二元政策一致性/不连贯性分析的主流方法。它们还强调了由机构安排和工作文化驱动的跨部门和跨标量协作经常被忽视的障碍的重要性。由此产生的类型将一致性的驱动因素和表现形式与对制度和社会的影响区分开来。由此，我们得出的结论是，一旦扣除当前的不连贯性成本，在执行《 2015年后议程》的过程中提高连贯性的情景就代表了社会的净收益，而仅代表机构的相对损失。但是，建立政策一致性的过程不容易解决，需要进行结构性更改。否则，机构就有可能陷入既昂贵又无效的表面上的连贯性。