References to studies excluded from this review Chan 2004A {published data only} Chan AW, Hrobjartsson A, Haahr MT, Gotzsche PC, Altman DG. Empirical evidence for selective reporting of outcomes in randomized trials: comparison of protocols to published articles.. JAMA 2004;291:2457-65. Hrobjartsson A, Chan AW, Haahr MT, Gotzsche PC, Altman DG. Selective reporting of positive outcomes in randomised trials-secondary publication. A comparison of protocols with published reports. Ugeskrift for Laeger 2005; 167:3189-91. Chan 2004B {published data only} Chan AW, Krleza-Jeric K, Schmid I, Altman DG. Outcome reporting bias in randomized trials funded by the Canadian Institutes of Health Research. CMAJ 2004;171:735-40. Cronin 2004 {published data only} Cronin E, Sheldon T. Factors influencing the publication of health research.