Does the definition of preventable emergency department visit matter? An empirical analysis using 20 million visits in Ontario and Alberta.

There is a substantial level of variation in prevalence estimates across definitions of preventable ED visits, and care should be taken when interpreting these estimates as each has a different meaning and may lead to different conclusions. The conceptualization and measurement of preventable ED visits is complex and multifaceted and may not be adequately captured by a single definition.