由Niti Aayog委托进行的一项新研究建议，将基础设施项目的社会折现率从8%上调至9.23%，期限最长为30年。
A new study commissioned by Niti Aayog has suggested revising the social discount rate to 9.23 per cent from 8 per cent for infrastructure projects with up to a 30-year horizon.
该研究名为《印度公共投资计划/项目评估的国家参数重新评估》，还建议将期限在30至50年之间的基础设施项目的社会折现率从8%下调至6.2%。社会折现率衡量的是当前消费与未来消费之间的社会权衡。它用于对今天实施的公共投资所产生的未来收益流进行折现。
The study titled 'Reassessment of National Parameters for Appraisal of Public Investment Programmes/Projects in India' further suggested revising the social discount rate downwards to 6.2 per cent from 8 per cent for infrastructure projects with horizons of 30-50 years. Social Discount Rate measures the societal trade-off between present consumption and future consumption. It is used to discount the future stream of benefits generated from public investments undertaken today.
期限较长的项目对未来经济增长率非常敏感，而这会影响社会折现率。
Projects with long time spans are sensitive to future economic growth rates, which impact the social discount rate.
Niti Aayog在2018年委托进行的这项研究曾建议，期限在50年以内的项目的社会折现率为8%，而长期基础设施和环境项目的折现率为6%。
The study commissioned by Niti Aayog in 2018 had recommended a social discount rate of 8 per cent for projects with horizons up to 50 years, with a lower rate of 6 per cent for long-gestation infrastructure and environmental projects.
该研究由E Somanathan、Monisankar Bishnu和Raavi Aggarwal在Niti Aayog的支持下完成，旨在开展独立的学术和政策导向研究。
The study has been prepared by E Somanathan , Monisankar Bishnu and Raavi Aggarwal pursuant to the support of Niti Aayog for the purpose of independent academic and policy-oriented research.
基础设施、能源、交通、城市服务和社会部门项目的公共投资决策通常通过经济成本效益分析来进行评估，这需要将未来的经济收益和成本折现到现值。只有当预期收益的现值超过预期成本的现值时，提案才被接受。
Public investment decisions across infrastructure, energy, transport, urban services and social sector programmes are generally appraised using economic cost-benefit analysis, which requires discounting future streams of economic benefits and costs into present values.A proposal is acceptable only if the present value of its expected benefits exceeds the present value of its expected costs. Any such comparison, therefore, requires an appropriate rate at which future economic benefits and costs are discounted, and that rate is termed SDR.
因此，任何此类比较都需要一个适当的折现率，这个折现率被称为社会折现率（SDR）。
PTI BKS BKS BALBAL.