Since inception of the Resource Management Act 1991 (RMA) the issue of sustainable management has dominated planning practice in New Zealand. Over the past decade, councils have wrestled with converting the concept of sustainable management into policy and practice. Implicit to the requirement that district councils develop plans for managing the environmental effects of the use and development of natural and physical resources is the assumption that good quality plans will result in improved environmental quality. The key question to be addressed in this paper is: Do good plans matter? Measuring the quality of plan implementation is a complex task, and little, if any, attempt has been made in councils to do it. The PUCM research is the first in New Zealand to attempt a quantitative analysis of the links between the quality of plans produced under the RMA and the quality of plan implementation. The purpose of this paper is to describe the methodology that we adopted for the research and to present some preliminary results from studying the implementation of plans through the resource consent process. Overall, we are trying to determine: how best to measure the quality of plan implementation and the effect that district plan quality has on implementation quality; and what factors influence the relationship between plan quality and implementation quality. This paper is structured into three main parts. The first is a description of the methodological approach taken to conduct the research. In the second part, the key preliminary results are presented. Finally the findings and the implications for achieving good environmental outcomes are discussed.