Examples of the four patterns of the distribution of the frequency of using ineffective interventions in patients.

Panel A: Almost always used: Nitrates on top of thrombolysis in acute myocardial infarction to reduce the mortality; Panel B: Rarely used: Hormone replacement therapy in menopausal women for secondary prevention of cardiovascular events; Panel C: Use sharply divided: H pylori eradication in H pylori positive people with gastro-oesophageal reflux disease; Panel D: No consensus on use: Calcium channel blockers for secondary prevention of ischeamic cardiovascular events.