Development of best practice principles for simplifying eligibility criteria.

Real world data is crucial for clinical research. In hospitals this information is more and more stored in electronic health records (EHR) and could be used for clinical trial feasibility and patient recruitment. On the other side eligibility criteria within study protocols are complex and usually not written in a way that is intuitively understandable or electronically usable. As part of overcoming the gap between eligibility criteria and the data that is available in EHRs we simplified eligibility criteria and created a guideline with best practice principles. The guideline explains how understandable criteria should be formulated and illustrates with examples what 'good' and 'bad' criteria are.