Ni Mhurchu et al. BMC Public Health 2010, 10:738 http://www.biomedcentral.com/1471-2458/10/738 one-fifth of zinc intake [9]. Children who miss breakfast have significantly worse daily nutrient intakes, including higher intakes of total fat, and lower intakes of dietary fibre and micronutrients than those who eat breakfast [9]. Hungry children may lack the energy and motiva- tion to become involved in classroom activities [10], while malnutrition and micronutrient deficiencies have been shown to impact on physical, mental, and social health, and reduce cognitive functioning [11-13]. A number of countries (e.g. United States, United Kingdom, Sweden) have government or non-government funded school breakfast programmes, which aim to pro- vide a free healthy breakfast to children and thereby improve nutrition and academic outcomes [14-16]. In New Zealand, some school breakfast programmes have been introduced in recent years, although none are offi- cial government programmes. The Red Cross Breakfast in Schools programme, which is available to decile 1 pri- mary schools (areas of low socioeconomic resource), was established in 2007 [17]. The programme is run with support from Countdown supermarkets (Progressive Enterprises) who supply breakfast foods free of charge. In 2008, the KickStart Breakfast programme for decile 1-4 schools (areas of low to moderate socioeconomic resource) was launched by Fonterra Co-Operative Group Limited and Sanitarium Health Food Company. Research indicates that school breakfast programmes have benefits in relation to nutrition, school attendance, academic performance and psychosocial function [14,18]. However, findings have been inconsistent, lim- ited by poor study design and methods, and frequently confuse correlation with causation. A Cochrane review identified seven randomised, controlled trials investigat- ing the effects of school feeding programmes (breakfast, lunch or snacks) [18]. However, only two were underta- ken in high income countries, one of which experienced substantial contamination between trial intervention groups [19], whilst the other did not include a full school breakfast (just milk) [20]. Based on all studies, the Cochrane review concluded that there is a dearth of high quality evidence on school feeding programmes and recommended further well-designed studies, parti- cularly cluster randomised controlled trials [18]. This paper presents the study protocol for a stepped wedge cluster randomised controlled trial to investigate the effects of a free school breakfast programme on stu- dents’ school attendance, academic achievement, psy- chosocial function, dietary habits and food security. Method/Design In New Zealand, there are two stages of schooling: pri- mary (years 0-8) and secondary (years 9-15). Primary schools include full primary (years 0-8), contributing (years 0-6) and intermediate (years 7-8) schools. There Page 2 of 6 are four terms in a primary school year, with term 1 starting in early February and term 4 ending in Decem- ber. All schools are assigned a decile rating, which indi- cates the extent to which the school draws its students from a range of socioeconomic areas. Decile 1 schools are the 10% of schools with the highest proportion of stu- dents from low socioeconomic resource areas (defined according to residents’ income, occupation, household crowding, educational qualifications and income support) and decile 10 are the 10% of schools with the highest proportion of students from high socioeconomic areas. Design The study is a stepped wedge cluster randomised con- trolled trial in which participating schools (clusters) cross over from control to intervention phase (i.e. one- way switch over) at different time points throughout the school year. The order of switch-over (’sequence’) is determined randomly for each group of clusters, and all clusters receive the breakfast programme intervention by the end of study (Figure 1). All schools start the trial at the same time point and act as controls until such time as they are randomised to crossover from control to intervention. The stepped wedge design is suitable for a phased evaluation approach, where the intervention is likely to do more good than harm, thus making it unethical to completely withhold the intervention from a control group, and/or where it is not possible to start delivery of the intervention to all participants at the same time [21]. Both of these criteria apply in this trial. Figure 1 Stepped wedge cluster randomised trial design.