Marine plastic pollution (MPP) is one of the most pressing issues especially for fast-growing economies in the Global South where addressing it involves both government and personal actions to achieve effective waste management policies. Alternative modelling strategies accounting for personal traits and beliefs (latent attitudes) which are unobservable characteristics are frequently overlooked in policy assessment studies. This study combines contingent valuation and latent traits questions to derive the willingness of Indonesian respondents to support MPP mitigation initiatives. One and two-step models are compared to test the sensitivity of results to modelling assumptions. Latent traits help to understand the willingness to pay (WTP) for MPP and one and two-step approaches produce comparable results. On average respondents are willing to pay £15, per person, per year to reduce MPP, or 2% of the average monthly salary. Local and international organizations should consider motivations and latent traits when designing MPP mitigation strategies.

海洋塑料污染 (MPP) 是最紧迫的问题之一，尤其是对于全球南方快速增长的经济体而言，解决该问题涉及政府和个人行动，以实现有效的废物管理政策。在政策评估研究中经常忽视作为不可观察特征的个人特征和信念（潜在态度）的替代建模策略。本研究结合了或有估值和潜在特征问题，以推导出印度尼西亚受访者支持 MPP 缓解举措的意愿。比较一步模型和两步模型以测试结果对建模假设的敏感性。潜在特征有助于了解 MPP 的支付意愿 (WTP)，一步法和两步法产生可比较的结果。平均而言，受访者愿意为每人每年支付 15 英镑以降低 MPP，即平均月薪的 2%。本地和国际组织在设计 MPP 缓解策略时应考虑动机和潜在特征。