This paper provides an account of how a ‘causal–process–tracing theory of change’ can be very helpful for programme prediction, planning and evaluation. The paper uses case studies as running examples to illustrate how this type of detailed theory of change would be built.

Based upon the theory of Emotional Contagion, the purpose of this investigation was to examine whether the use of positively-charged imagery could create a more positive exercise experience. Participants were randomly allocated into one of three test conditions ('neutral', 'happy' and control) whereupon they performed two step-aerobic sessions; baseline/ familiarisation and experimental. Upon completion of the trials various exercise related, psychological measures were taken (Session RPE, FS, Enjoyment and Subjective Exercise Experience). A 3 Â 2 Factorial MANOVA was used to assess for main effects and between condition interactions. There was no evidence of any effect for any of the DVs. ES data appeared to support this conclusion. Numerous recommendations are made to direct future research into this area.