Payback: The time, usually in years, from some point in the development process until the commercialized product or service has recovered its costs of development and marketing. While some firms take the point of full-scale market introduction of a new product as the starting point, others begin the clock at the start of development expense.
回报:产品或服务商业化以后所获收益与开发和市场成本相抵消的时间，通常以年计算。有的公司将新产品全面投入市场的时间作为起点，而有些公司以投入开发成本开始计算。
