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Table 3 Description and Examples of the Normalization Process of the Free-text Eligibility Criteria

From: Leveraging the EHR4CR platform to support patient inclusion in academic studies: challenges and lessons learned

Normalizing eligibility criteria in 6 steps Before normalization process After normalization process
1- Remove redundancy among inclusion and exclusion criteria IC: no contraindication to low weight molecular heparin
EC: any contraindication to low weight molecular heparin
EC: any contraindication to low weight molecular heparin
2- Identify individual criteria (e.g. split a single complex criterion into multiple simple criteria) IC: renal artery imaging dated less than 1 year confirming the existence of two normal-sized kidneys > 90 mm and showing no renal artery stenosis IC: renal artery imaging dated less than 1 year;
IC: kidney size > 90 mm;
IC: no renal artery stenosis
3- Reformulate criteria (e.g. negate and switch from inclusion to exclusion) IC: no renal artery stenosis EC: renal artery stenosis
(Negation removed)
4- Recognition of individual medical concepts: EC: known pregnancy or no effective contraception for women of childbearing age or breastfeeding - Pregnancy
- Effective contraception
- Age
- Breastfeeding
5- Remove semantic ambiguity (based on knowledge sources or human expertise) - Female contraception - Oral contraception
- Intrauterine device
- Diaphragm
- Spermicide
- Impossible follow-up - No translation
6- Translating medical concepts from local languages to English EC: Grossesse connue ou absence de contraception efficace pour les femmes en âge de procréer ou allaitement. EC: Known pregnancy or no effective contraception for women of childbearing age or breastfeeding
  1. IC inclusion criterion, EC exclusion criterion