As a Doctor, the potential for improvement begins from very basics. For instance - a radiologist sees a funny looking line on an xray and reports "this is probably nothing, but we should repeat the xray in 6 weeks to make sure." Sometimes these requests slip through the cracks and in a fraction of cases the patient presents 2 years later with terminal cancer from their metastatic lung Ca.

Ensuring blood thinners are prescribed post coronary bypass surgery or stenting is another one. It should happen every time, but sometimes by human error it may not.

A good startup idea would be to make a hotlist of the top ~1000 of these obvious, preventable errors, combine IT data sources to predict when they might be occuring, and have checking systems in place to prevent them. If it worked even adequately, hospitals would be seen as negligent for not using such a system.