Prolonged QT interval is known to be associated with life-threatening arrhythmias. Current ICH E 14 Guidance requests all sponsors submitting new drug applications to conduct a thorough QT/QTc study. A typical QTc study consists of four treatments, placebo, positive control and test treatment with therapeutical dose and test treatment with supra-therapeutical dose. ICH E14 recommended to perform non-inferiority testing by comparing means of both doses with mean placebo matched at each time point of interest. Assay sensitivity is carried out by comparing mean of positive control with mean placebo. We will discuss the statistical considerations of such tests and alternative approaches.