The Evidence-to-Practice Gap: Why It Takes 20 Years to Stop Doing Harm
The average lag between definitive evidence and guideline change was 10 to 20 years. For some practices, it was longer. The reasons haven’t changed.
Sixty practices. Two hundred and ten references. Four decades of change.
Over the past 10 weeks, this series has documented the rise and fall of 60 routine obstetric practices: 19 antepartum, 21 intrapartum, and 20 postpartum and neonatal. Every one was taught with authority. Every one was performed with confidence. Every one failed when subjected to rigorous scientific evaluation.
But the story is not just what we abandoned. The story is how long it took.
DES was prescribed for 18 years after a randomized trial showed it was ineffective. Routine episiotomy persisted for more than a decade after the Argentine Trial demonstrated it increased the injuries it claimed to prevent. Bed rest was prescribed for 30 years after Cochrane reviews showed no benefit for any indication. Continuous electronic fetal monitoring remains universal in American obstetrics 40 years after the Dublin trial showed it increased cesarean deliveries without improving neonatal outcomes.
The pattern is consistent. The average lag between publication of definitive evidence and meaningful change in clinical practice was 10 to 20 years. For some practices, the gap was longer. For a few, the gap has not closed at all.
This final post asks the question that matters most: why? And what would it take to close the gap?
🎯 Free Subscriber Bottom Line: Across 60 abandoned obstetric practices, the average time between definitive evidence and practice change was 10 to 20 years. Five forces consistently delayed change: medicolegal fear, financial incentives, training inertia, cognitive bias, and institutional resistance. The same forces are operating today. The question is not which current practices will be abandoned. The question is whether we will wait another 20 years.
Below, paid subscribers get: - The complete gap analysis across all 60 practices with data visualization - Categorization of drivers: what accelerates and what delays practice change - The master table: practice, year of evidence, year of guideline change, gap, primary driver of persistence - The practices most likely to appear on the 2065 list - A framework for accelerating evidence-to-practice translation - The case for why professional organizations must lead faster
