This is the first bronchiolitis study to examine the clinical and economic impact of making disposition decision on primarily clinical grounds, while blinding the physicians to oxygen saturations by providing them with either true saturation measurements or those which are 3 percentage points above the true values. Although physiologically insignificant and within the measurement error of the instrument, this difference has been shown to be perceived as clinically relevant and to have a major hypothetical impact on disposition, without any evidence to support this belief.