In Response to: “Using Lean-Based Systems Engineering to Increase Capacity in the Emergency Department

To the editor: We read with interest the article by White et al., “Using Lean-Based Systems Engineering to Increase Capacity in the Emergency Department,” in which the authors conclude that Lean could improve emergency department (ED) throughput and capacity. A number of other studies have also suggested that Lean is beneficial in addressing the problem of ED wait times. As in White et al., the vast majority of these studies have been conducted in single centers and/or as before-after evaluations.1-6 Moreover, publication bias likely also plays a role in the consistency of these findings since positive evaluations are more likely to be published.7 Although White et al. compared changes in ED length of stay with a concurrent population in their own center, it is not possible to generalize beyond this particular ED. We recently published a large multi-center controlled study of Lean in Ontario, Canada, (http://www.annemergmed.com/ article/S0196-0644%2814%2900516-2/fulltext) and found that while there were reductions in ED length of stay among the 36 hospitals that participated in the Lean program, similar reductions were observed among the 63 matched control hospitals over the same period. In our study, context was also important. Because Lean was part of a broader ED wait time strategy, including wait time targets, public reporting, and targeted financial incentives, it was clear that a wide array of incentives had an effect on wait times in all EDs across the region. Our conclusion is that single-center and before-after studies do not provide rigorous or generalizable evidence that Lean is effective in reducing ED length of stay. Decisions to implement should be based on solid evidence, since Lean initiatives typically require the engagement of external consultants and/or the dedication of significant internal resources for their development and implementation.