The relationship between clients and agencies involved in developing quality advertising campaigns has long been an area of interest for researchers. Much of the early research focussed on the factors which contributed to the origins, functioning and dissolution of client agency relationships in advertising. In addition much of this early research had considered these relationships from the point of view of the agency. In comparison this research considers the importance of collaboration in the development of quality advertising campaigns. The research considers the contribution of process and outcome factors in the development of advertising campaigns. To understand how these two groups of factors contribute to the development of quality advertising campaigns it was decided to use a mixed methods approach to conduct the research. Initially a series of exploratory in-depth interviews were undertaken with senior personnel from a range of major Auckland client companies and agencies. These interviews provided a range of rich qualitative data which was the basis for developing the quantitative questionnaire. This was followed by a comprehensive quantitative questionnaire that surveyed a range of people working at major New Zealand and Australian advertisers. The data collected in the quantitative segment of the research was then analysed. The analysis identified four factors likely to influence the quality of advertising campaigns produced. These were relationship stability, agency flexibility, agency competency and expertise and client involvement. The quantitative research showed clients who were involved in the development of campaigns were more likely to produce original campaigns that were also more creative, and as a result more effective. Clients and agencies that were in stable relationships were likely to produce campaigns which were both original and effective. Agencies that had high levels of competency and expertise were likely to produce campaigns which were more strategic and original. There was an inverse U relationship between competency and expertise and the effectiveness of campaigns produced. That is those with high and low levels of competency and expertise were likely to produce less effective campaigns than those with moderate levels of competency and expertise. Those clients and agencies that are in stable relationships and agencies that had high levels of competency and expertise were also likely to produce more creative campaigns. Agencies that were either inflexible or highly flexible are likely to produce the most original campaigns. Situations where the client was not involved nor were they in a stable relationship were likely to result in campaigns with less strategic focus. The results overall suggest that the process factors make a contribution throughout the process of developing a campaign and that the outcome factors are those which help the client to judge whether a campaign is high quality. Those who consider process factors such as trust to be contributors to the development of quality advertising campaigns, may really only “hope” that quality campaigns will result. This research has presented a clients’ view on the factors which are important to quality campaign development. This is in contrast to much of the earlier work developed which considered the agencies’ viewpoint. For agency managers who seek to develop quality campaigns it is important that they involve the client. They should also ensure that their relationship is stable, that they are flexible in their work with the client and they assign personnel who are competent and have the expertise necessary to develop quality advertising campaigns.