Evaluating Hispanic and Asian Name Algorithms as a Tool for 

Improving Linkage to the National Death Index 

Dean H. Judson, 

Eric Miller, 

Jennifer D. Parker, 

Hannah Day 

National Center for Health Statistics (NCHS) 

2013 Federal Committee on Statistical Methodology 

Disclaimer: These analyses were performed on an “almost final” 

file; a small handful of cases still need final resolution. 
Outline 

•		Describe goals and process 

•		Describe innovations 

• Focus on name algorithms/SSN4’s 

•		Describe operational results and evaluate 

effects 

•		Think about future evaluations 

2 
NCHS Linked Mortality Files
 

•		Last released in 2009 (up to NDI data year 

2006), linkage of survey respondents from 

NCHS surveys (now ~2.5M records) to the 

National Death Index (~70M records) to 

ascertain mortality status & causes of death 

•		Auxiliary data from the Social Security Death 

Master File (DMF) also used to ascertain 

status 

•		Used for passive follow-up epidemiological 

studies 

3 
Process 

• Construct submission files 

– Up to ~50 alternative records per person 

accounting for: 

• Alternative names (nicknames, middle/first flip) 

• Alternative dates of birth (esp. with imputations) 

• Alternative identifying numbers 

• Unique Hispanic and Asian naming conventions 

• Submit to NDI linkage 

• Potential links returned 

4 
Process (continued) 

• Reweight and rescore 

– Construct detailed weights based on name, dates, 

digits, and other characteristics’ frequencies 

– Wti=log2(1/Proportion), prorate for inexact matches 

– Sum weights and select “best” (highest scoring) pair 

– Tentatively flag records above threshold 

• Rule-based post-processing 

– Alternative to clerical review 

• Clerical review 

5 
Innovations this time
 

•		Hispanic and Asian name algorithms 

•		Hispanic nickname tables 

•		New use of phonetic algorithms: 

– NYSIIS, Soundex, Jaro-Winkler score, Edit distance, 

“within” 

•		Use of enhanced matching macro (citation: 

Dean Resnick) to search the DMF 

•		Enhanced weights 

•		Rule-based post-processing 

•		Expedited/Computerized clerical review 

•		4-digit SSN NDI search (completely new) 

6 
Example of potential for linkage 

error - Hispanic Paradox 

•		 Hispanics have lower mortality rates compared to nonHispanic whites 

–		Health selective immigration 

–		Salmon bias (return migration) 

–		Advantageous health behaviors and social support 

–		Data quality / Insufficient linkage 

• Naming conventions for Hispanics differ from other US populations 

– Use of mother’s and father’s surname 

– May not have single middle name 

• Less likely to have social security number 

– Especially among older adults and foreign born 

7 
Methods – Name Clean-up 

– Accounting for Hispanic and Asian naming 

conventions 

• Hispanic 

– Hispanic nickname lookup table 

– switch middle and last 

• Asian 

– switch first and last 

8 
Hispanic Nickname Table
 

Sex Formal Name Nicknames 

F Adelina Deli Lina 

F Adelaida Ade Adela 

M Adrián Adri 

F Adriana Adri 

M Alberto Alber Albertito Beto Berto Tico Tuco Tito 

M Alejandro Ale Álex Alejo Jandro Jano Sandro 

F Alejandra Sandra Ale Álex Aleja Jandra Jana 

M Alfonso Alfon Fon Fonso Fonsi Poncho 

F Alicia Ali Licha 

9 
NDI Selection Algorithm
 

10 

NDI Selection Criteria

Criterion one Criterion two Criterion three

Social Security Number X X

First name X X

Middle initial 

Last name X X

Day of birth X X

Month of birth X X

Year of birth X X

Sex X

Father’s surname 

Race 

State of residence 

State of birth 

Marital Status 
 

 

 

 

 

 

 

 

Basic Tabulations 

-> eligible = NO 

Rejected by | 

NDI | Freq. Percent Cum. 

------------+-----------------------------------

NO | 169 0.12 0.12 

YES | 143,835 99.88 100.00 

------------+-----------------------------------

Total | 144,004 100.00 

-> eligible = YES 

Rejected by | 

NDI | Freq. Percent Cum. 

------------+-----------------------------------

NO | 2,478,065 99.09 99.09 

YES | 22,862 0.91 100.00 

------------+-----------------------------------

Total | 2,500,927 100.00 

11 
Eligible Record Dispositions
 

12 

 Final disposition |

 class, among | Final NDI Status

 eligibles | ALIVE DEAD | Total

----------------------+----------------------+----------

 Assumed alive | 2,087,704 0 | 2,087,704 

 | 100.00 0.00 | 84.25 

----------------------+----------------------+----------

 Dead by score/class | 0 382,334 | 382,334 

 | 0.00 97.94 | 15.43 

----------------------+----------------------+----------

 Dead by rule | 0 3,327 | 3,327 

 | 0.00 0.85 | 0.13 

----------------------+----------------------+----------

Dead by manual review | 0 1,848 | 1,848 

 | 0.00 0.47 | 0.07 

----------------------+----------------------+----------

Dead by mult. sources | 0 2,852 | 2,852 

 | 0.00 0.73 | 0.12 

----------------------+----------------------+----------

 Total | 2,087,704 390,361 | 2,478,065 

 | 100.00 100.00 | 100.00 
Rescore 

• Five “classes” 

–		One: Full hit on 8 or 9 fields, incl. SSN 

–		Two: SSN present almost exact 

–		Three: SSN unknown, 8 or 9 other fields
 

–		Four: SSN unknown, <8 other fields 

–		Five: SSN < 8 digits, not in classes one-four 

•		Scores = sum of fields weights with 

proration for partial matches 

•		Thresholds by class (NHEFS) 

13 
Eligible Record Dispositions by Class
 Final disposition |

 class, among | Rescore Class

 eligibles | 1 2 3 4 5 . | Total

----------------------+------------------------------------------------------------------+----------

 Assumed alive | 4 1,228 23,083 802,162 474,065 787,162 | 2,087,704

 | 0.00 1.32 24.00 98.00 99.73 100.00 | 84.25

----------------------+------------------------------------------------------------------+----------

 Dead by score/class | 207,690 90,392 71,032 13,220 0 0 | 382,334

 | 100.00 97.01 73.87 1.62 0.00 0.00 | 15.43

----------------------+------------------------------------------------------------------+----------

 Dead by rule | 0 966 1,265 760 336 0 | 3,327

 | 0.00 1.04 1.32 0.09 0.07 0.00 | 0.13

----------------------+------------------------------------------------------------------+----------

Dead by manual review | 0 137 543 1,159 9 0 | 1,848

 | 0.00 0.15 0.56 0.14 0.00 0.00 | 0.07

----------------------+------------------------------------------------------------------+----------

Dead by mult. sources | 0 453 238 1,225 936 0 | 2,852

 | 0.00 0.49 0.25 0.15 0.20 0.00 | 0.12

----------------------+------------------------------------------------------------------+----------

 Total | 207,694 93,176 96,161 818,526 475,346 787,162 | 2,478,065

 | 100.00 100.00 100.00 100.00 100.00 100.00 | 100.00

14 
Innovations 

• Rules 

– E.g. Rule 2: if social security matches on 8 or 

9, last name matches, sex matches, exact 

DOB, and birth state matches or is missing, 

then match=yes (dead). 

• Collectively referred to as “autodead”, 

“autoalive”, “autoreview” 

• Clerical review screens to follow 

15 
Dispositions by “Auto” Rules
 

16 

 Final disposition |

 class, among | Auto-dead rule fired

 eligibles | N Y . | Total

----------------------+---------------------------------+----------

 Assumed alive | 1,299,062 1,480 787,162 | 2,087,704 

 | 99.56 0.38 100.00 | 84.25 

----------------------+---------------------------------+----------

 Dead by score/class | 979 381,355 0 | 382,334 

 | 0.08 98.76 0.00 | 15.43 

----------------------+---------------------------------+----------

 Dead by rule | 0 3,327 0 | 3,327 

 | 0.00 0.86 0.00 | 0.13 

----------------------+---------------------------------+----------

Dead by manual review | 1,848 0 0 | 1,848 

 | 0.14 0.00 0.00 | 0.07 

----------------------+---------------------------------+----------

Dead by mult. sources | 2,852 0 0 | 2,852 

 | 0.22 0.00 0.00 | 0.12 

----------------------+---------------------------------+----------

 Total | 1,304,741 386,162 787,162 | 2,478,065 

 | 100.00 100.00 100.00 | 100.00 
Dispositions by “Auto” Rules
 

 Final disposition |

 class, among | Auto-alive rule fired

 eligibles | 0 1 . | Total

----------------------+---------------------------------+----------

 Assumed alive | 797,632 502,910 787,162 | 2,087,704 

 | 67.15 99.95 100.00 | 84.25 

----------------------+---------------------------------+----------

 Dead by score/class | 382,331 3 0 | 382,334 

 | 32.19 0.00 0.00 | 15.43 

----------------------+---------------------------------+----------

 Dead by rule | 3,327 0 0 | 3,327 

 | 0.28 0.00 0.00 | 0.13 

----------------------+---------------------------------+----------

Dead by manual review | 1,828 20 0 | 1,848 

 | 0.15 0.00 0.00 | 0.07 

----------------------+---------------------------------+----------

Dead by mult. sources | 2,631 221 0 | 2,852 

 | 0.22 0.04 0.00 | 0.12 

----------------------+---------------------------------+----------

 Total | 1,187,749 503,154 787,162 | 2,478,065 

 | 100.00 100.00 100.00 | 100.00 

17 
Clerical Review Slide 

18
[ii] Microsoft Access 

Efil Manual Review Form 

ubmission Recor<!J DMF Record ring Comparators I ============-----=========~ 

DMF _!J Submission NDI 

Name Match Name Match Name 

First: IHany iCJln CXJ lnean 

Middle: In J CJ !Harold [IJIH 

Last: !Judson J CXJ !Judson CXJ IJudson 

Suffix: I V erify!Proof: I v 

DMF SSN Matching Digits Submission Matching Digits NDI SSN 11 

0000 12654 l-----XXXX ICIJIXXXXX2654 l-----XXXX ICIJIXXXXX2654 Sub. NDI 

Birth Date 

DMF Match 

Month:! 07 I X I J 

Day: -, - 2-8 I 11 

Year: I 1988 I +26 11 

Sub. 

07 I 

20 1 

1962 I 

State Birth: ]er IMI 

De State Res: ,.....J MD--IMD ath Date 

DMF Match NDI 

12 1 x I 12 DMF I 

Ol I IJ 24 State Country Code: 

2011 1 X J 2011 ZipLast ResJ,...... MD _ _ 

ZipLump: ] 

Last Alive Linkage ID: Reviewer:IVVV6 Date:] Review: I Eind I 

Year: f2Q68 J 1000000000000 1 ...... RJev e\1 te s: ________ <S No Match I I 

I .L-vvo I ~,Save Rec. # I 1156 SCORE:! 45 <S Unsure · 

_!J CLASS:! 2 IS Match Back I Next I 

Reason: IDEA 'S SPECIAL PIT 17 DMF Match OQuit I ~ I 

Form View I Num Lock Filtered § ~ _,,; 

19
 
Some Operational Results 

• Interrater reliability (clerical review) 

• Overall link rates by race/ethnicity 

• 4-digit SSN vs. 9-digit SSN match rate
 

20 

Interrater Reliability Table

NO MATCH MATCH TOTAL

108 11 119

49.1 5.0 54.09

90.8 9.2 -

83.7 12.1 -

18 79 97

8.2 35.9 44.09

18.6 81.4 -

14.0 86.8 -

126 90 216

58.64 41.36 100

Cohen's Kappa: 0.727

NO MATCH

MATCH

TOTAL
Disposition by Race/Ethnicity
 Final disposition |

 class, among | Race/Ethnicity

 eligibles | White-Non Black-Non API-Non AIAN-Non Hispanic Other | Total

----------------------+------------------------------------------------------------------+----------

 Assumed alive | 1,306,474 306,850 66,917 13,488 313,848 80,127 | 2,087,704 

 | 81.11 85.30 93.24 85.46 93.86 93.48 | 84.25 

----------------------+------------------------------------------------------------------+----------

 Dead by score/class | 298,531 51,760 4,755 2,250 19,713 5,325 | 382,334 

 | 18.53 14.39 6.63 14.26 5.90 6.21 | 15.43 

----------------------+------------------------------------------------------------------+----------

 Dead by rule | 2,690 352 27 25 170 63 | 3,327 

 | 0.17 0.10 0.04 0.16 0.05 0.07 | 0.13 

----------------------+------------------------------------------------------------------+----------

Dead by manual review | 1,209 305 26 9 229 70 | 1,848 

 | 0.08 0.08 0.04 0.06 0.07 0.08 | 0.07 

----------------------+------------------------------------------------------------------+----------

Dead by mult. sources | 1,789 458 42 11 424 128 | 2,852 

 | 0.11 0.13 0.06 0.07 0.13 0.15 | 0.12 

----------------------+------------------------------------------------------------------+----------

 Total | 1,610,693 359,725 71,767 15,783 334,384 85,713 | 2,478,065 

 | 100.00 100.00 100.00 100.00 100.00 100.00 | 100.00 

21 
Nine-digit SSNs
 

22 

 Final disposition | Full 9-digit SSN

 class, among | present

 eligibles | NO YES | Total

----------------------+----------------------+----------

 Assumed alive | 1,488,698 599,006 | 2,087,704 

 | 94.74 66.07 | 84.25 

----------------------+----------------------+----------

 Dead by score/class | 77,896 304,438 | 382,334 

 | 4.96 33.58 | 15.43 

----------------------+----------------------+----------

 Dead by rule | 1,923 1,404 | 3,327 

 | 0.12 0.15 | 0.13 

----------------------+----------------------+----------

Dead by manual review | 1,569 279 | 1,848 

 | 0.10 0.03 | 0.07 

----------------------+----------------------+----------

Dead by mult. sources | 1,315 1,537 | 2,852 

 | 0.08 0.17 | 0.12 

----------------------+----------------------+----------

 Total | 1,571,401 906,664 | 2,478,065 

 | 100.00 100.00 | 100.00 
Four-digit SSNs, 2007+
 

23 

 Final disposition | last four SSN digits

 class, among | only

 eligibles | NO YES | Total

----------------------+----------------------+----------

 Assumed alive | 2,064,166 23,538 | 2,087,704 

 | 84.15 93.86 | 84.25 

----------------------+----------------------+----------

 Dead by score/class | 380,806 1,528 | 382,334 

 | 15.52 6.09 | 15.43 

----------------------+----------------------+----------

 Dead by rule | 3,319 8 | 3,327 

 | 0.14 0.03 | 0.13 

----------------------+----------------------+----------

Dead by manual review | 1,843 5 | 1,848 

 | 0.08 0.02 | 0.07 

----------------------+----------------------+----------

Dead by mult. sources | 2,852 0 | 2,852 

 | 0.12 0.00 | 0.12 

----------------------+----------------------+----------

 Total | 2,452,986 25,079 | 2,478,065 

 | 100.00 100.00 | 100.00 
9-digit SSNs, 2007+, NHANES
 

24 

 Final disposition |

 class, among | 9-digit SSN, 2007+

 eligibles | NO YES | Total

----------------------+----------------------+----------

 Assumed alive | 2,080,957 6,747 | 2,087,704 

 | 84.22 94.59 | 84.25 

----------------------+----------------------+----------

 Dead by score/class | 381,949 385 | 382,334 

 | 15.46 5.40 | 15.43 

----------------------+----------------------+----------

 Dead by rule | 3,326 1 | 3,327 

 | 0.13 0.01 | 0.13 

----------------------+----------------------+----------

Dead by manual review | 1,848 0 | 1,848 

 | 0.07 0.00 | 0.07 

----------------------+----------------------+----------

Dead by mult. sources | 2,852 0 | 2,852 

 | 0.12 0.00 | 0.12 

----------------------+----------------------+----------

 Total | 2,470,932 7,133 | 2,478,065 

 | 100.00 100.00 | 100.00 
Demographic Analysis
 

25 
Demographic Analysis, Hispanics
 

26 

0

25 50 75

100

5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90

5-year age groups

Sex ratio, alive records Sex ratio, 2010 Census

Sex ratios by Five-Year Age Groups, Hispanic only
Conclusions and Future Research 

•		Limited success with Hispanic and Asian 

name algorithms 

•		Some success with four-digit SSN algorithm 

•		Good success with demographics 

•		More mysteries, more evaluation! 

•		Future: Latent class modeling, error bars, etc.
 

27