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Table 1 Matching rates based on different matching criteria

From: Comparison of birth certificates and hospital-based birth data on pregnancy complications in Los Angeles and Orange County, California

   Number Percentage based on Memorial Care data Percentage based on birth certificate data
Matched records      62200 85.79 % 86.98 %
   Matching Variables    
  Types of matching DOB of child Delivery hospital DOB of mother Mother’s name    
1. Exact match on four variables Exact Exact Exact Exact 59105 81.52 % 82.65 %
2. Exact match on three variables Exact Exact Partiala Exact 2869 3.96 % 4.01 %
3. Exact match on three variables Exact Exact Exact Partialb 120 0.17 % 0.17 %
4. Exact match on two variables Exact Exact Partiala Partialb 106 0.15 % 0.15 %
Unmatched records in Memorial Care data with non-missing matching variables 4162 5.74 %  
Unmatched records in Memorial Care data with missing matching variables 6138 8.47 %  
Unmatched records in birth certificate data 9312   13.02 %
  1. amatched by any two of the three fields: year, month, and day
  2. bmatched by the first three characters in both the first name and the last name of the mother