Understanding how policy and policy-making processes can influence the speed and direction of socio-technical change is an important, yet underexplored research agenda in the field of sustainability transitions. This paper is the first application of a novel analytical framework which conceptualises the co-evolutionary dynamics of policy mixes and socio-technical systems, by complementing the sustainability transitions and policy mix literatures with insights from policy feedback theory. Our paper is an in-depth empirical case study of the zero carbon homes policy mix in the UK which sought to promote radical change in the UK house building system. Our paper makes three contributions. First, it makes an empirical contribution by analysing an example of an ambitious policy strategy in the housing sector where various policy effects and feedback mechanisms led to a loss of political support for the target, eventually leading to its abandonment, and only limited change within the socio-technical system. Second, our paper produces novel insights about the effects of policy mix credibility on socio-technical change, and the underlying feedback mechanisms which influence its formation and loss. Finally, based on our empirical analysis we propose conceptual refinements to the co-evolutionary framework and suggest avenues for future research explaining the dynamics of feedbacks between policy mixes and socio-technical systems. From the empirical analysis a key finding is that policy mixes need to be effectively designed in order to produce positive feedback from the outset, through the creation of resources, provision of clear information and the creation of credibility, and reforming conflicting institutional supports. In the case, ineffective initial design led to uncertainty and inertia, which did not generate sufficient positive feedback to withstand adverse economic and political conditions later on, which ultimately contributed to the abandonment of the policy mix.

理解政策和决策过程如何影响社会技术变革的速度和方向，是在可持续发展领域中一项重要但尚未充分研究的研究议程。本文是一种新颖的分析框架的首次应用，该框架通过用政策反馈理论的见识补充可持续发展和政策组合文献，概念化了政策组合和社会技术系统的共同进化动力学。本文是对英国零碳房屋政策组合的深入经验案例研究，旨在促进英国房屋建筑系统的根本变化。我们的论文做出了三点贡献。第一，它通过分析住房部门雄心勃勃的政策策略的示例做出了实证性贡献，该案例中各种政策效果和反馈机制导致对目标的政治支持丧失，最终导致目标的放弃，并且在社会经济领域内只有有限的变化。技术系统。其次，我们的论文对政策组合信誉对社会技术变革的影响以及影响其形成和损失的潜在反馈机制产生了新颖的见解。最后，基于我们的经验分析，我们提出了对共同进化框架的概念完善，并为未来的研究提供了途径，以解释政策组合和社会技术系统之间的反馈动态。从经验分析中得出的一个关键发现是，需要有效地设计政策组合，以便从一开始就通过创建资源，提供清晰的信息和建立信誉以及改革相互矛盾的制度支持来产生积极的反馈。在这种情况下，无效的初始设计会导致不确定性和惯性，而这种不确定性和惯性并没有产生足够的积极反馈来承受以后不利的经济和政治条件，最终最终导致了政策组合的放弃。