Table 7.
Summary of System Features by Scheme
| Feature | READ | SNOMED | UMLS |
|---|---|---|---|
| Complete | .57 | .70 | .50 |
| Clear1 | 1.00 | .86 | .96 |
| Mapping2 | .41 | .21 | .36 |
| Compositional | Partial | Yes | No |
| Synonyms | Yes | Yes | Yes |
| Attributes and uncertainty | Yes (qualifiers) | Yes (modifier axis) | No |
| Taxonomy3 | 2.14 | 4.56 | 3.17 |
| Meaningless identifiers | Yes | No | Yes |
| Unique identifiers | Yes | Yes | Yes |
| Definitions4 | 0.00 | 0.00 | .49 |
| Language independence | English only | English, French, Chinese and Portuguese | (English, French, German, Portuguese, Spanish5) |
| Syntax/grammar | Yes (qualifier mapping) | No | N/A (precoordinated) |
1
Score for clarity = (1-duplication rate)
2
Fraction of candidate concepts with administrative mapping
3
Number of first-degree relatives per concept
4
Fraction of concepts with definitions provided
5
MeSH terms only