Reply to "Letter to Editor Concerning the Article—Effect of the World Health Organization Checklist on Patient Outcomes: A Stepped Wedge Cluster Randomized Controlled Trial". Issue 2 (February 2016) - Haugen, Arvid Steinar; Søfteland, Eirik; Almeland, Stian Kreken; Sevdalis, Nick; Vonen, Barthold; Eide, Geir Egil; Nortvedt, Monica Wammen; Harthug, Stig