Realist review to understand the efficacy of school feeding programmes

Publisher Website
Google Scholar
Abstract
Review methodsWe analysed the 18 studies (reported in 29 articles) included in our Cochrane review2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 using the methods of a realist review. Realist review exposes and articulates the mechanisms by which the primary studies assumed the interventions to work (either explicitly or implicitly); gathers evidence from primary sources about the process of implementing the intervention; and evaluates that evidence so as to judge the integrity with which each theory was actually tested and (where relevant) adjudicate between different theories.31 32We read, re-read, and discussed the papers and constructed a matrix on an Excel spreadsheet to collate information for each trial on: Study design, sample size, and outcome data Nature of the experimental and (where present) control interventions, including intensity and timing Process detail, especially comments on the fidelity of the intervention, changes made by staff on the ground, and reasons for those changes Aspects of the study's history and context, especially those highlighted as important by the study's authors Any theories or mechanisms postulated (or assumed) by the study's authors to explain the success or failure of the programme. We considered relevant data first on a trial by trial basis in terms of the interaction between context, mechanism, and outcome, and then across the different trials to detect patterns and idiosyncrasies. We discussed preliminary conclusions and synthesised key findings using a narrative and interpretive approach.33 We identified four broad areas relevant to this analysis: the historical context of school feeding programmes (see bmj.com), theories to explain the success of particular programmes (box 1), theories to explain their failure or qualify a partial success (box 2); and measurement issues (see bmj.com).Box 1 Process factors that seem to enhance efficacy of school feeding programmesStrong process evidence across many trials Target group has clear nutritional deficiency (usually, inadequate energy intake) and trial is oriented to correcting this rather than to short term hunger relief Well organised schools that form part of an efficient distribution chain for the supplement Intervention developed with local teams rather than designed by distant experts Supplement is piloted to exclude intolerance and confirm palatability and acceptability Measures are in place to ensure that the food supplement is consumed (eg close supervision of eating) In disaffected young people, attention is paid to social aspects of the meal Limited process evidence from one or few trials Use of local ingredients and cooking methods In extreme poverty, intervention is designed so that attending school is more economically viable than keeping children at home Intervention seeks to induce a change in home diet by educating or inspiring children Possible factors that might be tested in future studies Better nutrition and health literacy in this generation reduces intergenerational cycle of poverty Box 2 Process factors that seem to reduce the efficacy of school feeding programmes Participants not aware of, signed up to, or trained to take account of the research dimension of the trial Study design involves role conflict or ethical difficulties for staff (eg requirement to serve nutritious meal to some but not all undernourished children) Insufficient measures in place to reduce confounding (eg controlling for benevolent attention) Adverse prevailing policy climate (eg policy conflicts with trial protocol or prompts rebranding of mainstream activity to gain research funding) Measurement issues (see bmj.com)