Lydia Bals identifies different types of offshoring, concluding that the buy option of offshore outsourcing versus hybrid or make options is directly related to purchasing. Her in-depth analysis specifically focuses on the sourcing of marketing services. In this context, the investigations of purchasing/marketing integration provide a conceptual model of barriers to purchasing involvement in sourcing of services. Moreover, she seeks to shed light on issues of providing incentives for advertising agencies from an agency theory perspective.

