Before and after studies and historical controls. Is the proof in the pudding?

Statistically Speaking: Demystifying MethodsBefore and after studies and historical controls.Is the proof in the pudding?Delivering definitive airway management using rapid sequence induction in a pre-hospital setting can indeed be a daunting task with little margin for error.Minor infractions at any step in the sequence can rapidly culminate to create an airway catastrophe.Nowhere else would the aggregation of marginal gains [1] reap more benefit than in such adverse conditions.In this issue of Anaesthesia, Angerman and colleagues [2] evaluated the effect of introducing a videolaryngoscope and a bougie into a standardised protocol for airway management.They demonstrated > 12% increase in first-attempt tracheal intubation success in a 'before and after' comparison.As it is widely accepted that airway complications increase with the increased number of attempts, this would represent a potentially significant improvement in patient care [3].