Using ex ante analysis to predict policy outcomes is common practice in the world of infrastructure planning. However, accounts of its uses and merits vary widely. Advisory agencies and government think tanks advocate this practice to prevent cost overruns, short-term decision-making and suboptimal choices. Academic studies on knowledge use, on the other hand, are critical of how knowledge can be used in decision making. Research has found that analyses often have no impact at all on decision outcomes or are mainly conducted to provide decision makers with the confidence to decide rather than with objective facts. In this paper, we use an ethnographic research design to understand how it is possible that the use of ex ante analysis can be depicted in such contradictory ways. We suggest that the substantive content of ex ante analysis plays a limited role in understanding its depictions and uses. Instead, it is the process of conducting an ex ante analysis itself that unfolds in such a manner that the analysis can be interpreted and used in many different and seemingly contradictory ways. In policy processes, ex ante analysis is like a chameleon, figuratively changing its appearance based on its environment.

在基础架构规划领域中，使用事前分析来预测政策成果是常见的做法。但是，其用途和优点的说明差异很大。咨询机构和政府智囊团提倡这种做法，以防止成本超支，短期决策和次优选择。另一方面，关于知识使用的学术研究对于如何在决策中使用知识至关重要。研究发现，分析通常对决策结果根本没有影响，或者主要是为了使决策者有信心做出决策而不是客观事实。在本文中，我们使用人种学研究设计来了解如何有可能以这种矛盾的方式描述事前分析的使用。我们建议事前分析的实质性内容在理解其描述和用途方面起着有限的作用。取而代之的是，进行事前分析本身的过程以这样一种方式展开，即可以以许多不同的看似矛盾的方式来解释和使用该分析。在政策制定过程中，事前分析就像变色龙一样，根据其环境形象地改变外观。