Product-Service Systems (PSS) have emerged as a key concept to meet the societal and market trends of increasing customer needs through the entire life-cycle. Unfortunately, several companies are struggling with getting revenues from service investments and translating 'real needs' to design improvements. The demand of the designer to go beyond the Voice of the Customer (VoC) is evident. This paper aims to map the interventions proposed by research in the area of PSS and VoC. Using a systematic mapping approach, the research domain was analyzed with regards to context and interventions. The results show a progressive development in the research area with a focus on the specification and realization of needs. A gap exists in connecting the engineers with 'real needs' and integrating the customer as a natural part of the entire development cycle of a PSS. By performing a systematic mapping, future research can be more focused and hopefully increasing its impact.