White and Bruning (2005) distinguished two sets of writing beliefs: transactional and transmissional beliefs. In this paper we analyse their beliefs scale and suggest two hypotheses about how such beliefs relate to writing performance. The single-process hypothesis treats the beliefs as different amounts of engagement, whereas the dual-process hypothesis claims that the beliefs represent different types of engagement. We then describe the results of an experiment with 84 university students as participants that assessed the relationship between writing beliefs, different forms of pre-planning and different aspects of writing performance.Our results support the dual-process hypothesis, and suggest that transactional beliefs are about the preference for a top-down strategy or a bottom-up strategy, while transmissional beliefs are about the content that is written about. These beliefs interact in their effects on text quality, the amount and type of revision carried out, and the extent to which writers develop their understanding. They also moderate the effectiveness of outlining as a strategy.