User's Guide

 

Table of Contents

• Chapter 1 - How to Use the NDI: Steps in the Process
• Chapter 2 - Preparing Your Records: Record Layout and Coding Specifications
  • Exhibit 1 - NDI User Records, Sample Format
  • Exhibit 2 - NDI User File Format and Coding Specifications
  • Exhibit 3 - Coding Instructions for Names
  • Exhibit 4 - State (or Foreign Country) of Residence, Birth and Death
• Chapter 3 - Your NDI Results (Coming Soon!)
• Chapter 4 - Assessing the NDI Output  (Coming Soon!)
• Appendix A - A Probabilistic Scoring Approach for Assessing NDI Match Results (Coming Soon!)

 

If you would like to receive an e-mail attachment containing a draft of the entire User's Guide, please send an email to ndi@cdc.gov to request the draft.

  

Chapter 1

How to Use the National Death Index (NDI): Steps in the Process

1. Download the NDI Application Form from the NDI website. (Allow approximately two to three months for your application to be reviewed and approved.)
2. To make the application process smoother, please call NDI staff on 301-458-4444 before completing the application form.
3. Email your unsigned NDI Application Form to ndi@cdc.gov. (This submission does not need to be accompanied by a copy of your IRB approval document.)
4. NDI staff will respond by emailing your assigned NDI number. Then, in about a week NDI staff will let you know whether your application might need revisions before you submit your final application.
5. Express mail your final, signed NDI Application Form and IRB approval to NCHS. Email us at ndi@cdc.gov or call 301-458-4444 to confirm that we received your package. 
6. Your application will be mailed to a 12-member panel for review and comment.
7. While your application is being reviewed, you can begin preparing your study subjects’ records for submission on a CD. Carefully follow the specifications in Chapter 2 of this User’s Guide. (Note: We require that you password protect your files using any self-decrypting software, such as PointSec, PGP, or WinZip. Call us if you need to make other arrangements for transmitting your data.)
8. You will receive a letter of approval and a blank NDI Transmittal Form when your application is approved.
9. Express mail your CD’s containing file(s) of study subjects’ records to NCHS. Include a separate NDI Transmittal Form for each file, a Worksheet for Calculating NDI Charges, and your check or purchase order. Then email us your  express mail tracking number and your password to open your files.
10. NDI staff will express mail a password protected CD containing your NDI search results in about two weeks. Your original CD will be returned in the same package.
11. Assess your results to identify the true matches using your own assessment criteria and/or the suggested NDI assessment criteria. You also have the option of purchasing death certificates directly from the state vital statistics offices—for all true matches or just for those matches you feel are questionable.
12. If additional NDI searches are needed in the future for the same study or project, first mail NCHS a signed NDI Repeat Request Form. (You will receive a new Repeat Request Form each time you receive your NDI results.) As soon as you receive a letter approving your repeat request (usually within 2 weeks), you may submit your new files for an NDI search.

NOTE: Whenever you have questions, please call us on 301-458-4444 or email us at ndi@cdc.gov. When emailing, always include your phone number and assigned NDI number.

 

Chapter 2

Preparing Your Records:  Record Layout and Coding Specifications

1. Records of study subjects must be created in a standard TEXT FILE (flat file) format.
2. Each record must contain exactly 100 positions (containing letters, numbers or blanks) and should have a carriage return at the end.
3. To be eligible for an NDI search, each record must contain at least one of the following combinations of data items:
   • FIRST and LAST NAME and SOCIAL SECURITY NUMBER
   • FIRST and LAST NAME and MONTH and YEAR OF BIRTH
   • SOCIAL SECURITY NUMBER and full DATE OF BIRTH and SEX
4. DO NOT USE ANY DELIMITERS SUCH AS TABS OR COMMAS TO SEPARATE THE DATA ELEMENTS.
5. Each data element must be put in its specified positions. See EXHIBIT 1 for sample user records in the required record layout.
6. Refer to EXHIBIT 2 for the file format and coding specifications for each data element.
7. Coding instructions for NAMES appear in EXHIBIT 2A.
8. State codes appear in EXHIBIT 2B.
9. An NDI TRANSMITTAL FORM must accompany each file submitted for an NDI search.  A blank NDI Transmittal Form(s) containing your assigned NDI search numbers will be sent to you with the letter approving your NDI search.
10. Only submit your records on a CD-ROM. If you put more than one file on the CD or diskette, it is helpful to use your assigned NDI numbers in your file names. Also print your assigned NDI numbers on the outside of your CD. We require that you password protect your file(s) using  any self-decrypting software.
11. Express mail your files(s), Transmittal Form, fee worksheet, and  check or purchase order to:
    NATIONAL DEATH INDEX
    National Center for Health Statistics
    3311 Toledo Road, Room 7318
    Hyattsville, MD 20782
    Phone: 301-458-4444
12. E-mail ndi@cdc.gov to confirm that your file(s) was received. Include your NDI number, the date the file was sent, and your express mail tracking number. If your file(s) is password protected, Also include your password(s) to open your files(s).

 

Exhibit 1:  NDI User Records, Sample Format

Create in a standard format text file, 100 positions per record, with no tabs, commas or other delimiters.

 

Positions of NDI Data Items

Select one of the items below for more information on a specific Data Element in a NDI User Record

 

Exhibit 2 - NDI User File Format and Coding Specifications

 

DATA ELEMENTS	POSITION	CODE STRUCTURE		CODING INSTRUCTIONS
1. Name of Person in the Study Group				See EXHIBIT 3 for instructions for coding surnames, first names, and middle initials. Both LAST name and FIRST name must be provided or the record will automatically be rejected unless the record contains a Social Security Number, a date of birth and a sex code. An initial in the FIRST name field is permitted.  (See minimum NDI eligibility requirements.)
Last Name	1-20	Alpha, left justified
First Name	21-35	Alpha, left justified
Middle Initial	36	Alpha or blank
2. Social Security Number	37-45	Numeric or blank		Must have 9 digits. If less than 9 or partial number, skip the field. If more than 9 digits, enter the first 9 digits. If two Social Security numbers are available, create a second submission record. If the number is unknown or not provided, leave the field blank. If SOCIAL SECURITY NUMBER is not provided, the MONTH and YEAR OF BIRTH and FIRST AND LAST NAME must be provided or the record will automatically be rejected.  (See minimum NDI eligibility requirements.)
3. Date of Birth				The months of January-September and the days 1-9 must have leading zeros. If either MONTH or YEAR of BIRTH is not provided, the SOCIAL SECURITY NUMBER and FIRST AND LAST NAME must be provided or the record will automatically be rejected.  (See minimum NDI eligibility requirements.) If only a person?s YEAR of BIRTH is known, you should consider the merits of preparing 12 duplicate records, one for each possible MONTH of BIRTH. This is especially important when the SOCIAL SECURITY NUMBER is not known. There is no charge for duplicate records.
Month	46-47	January	01
		February	02
		March	03
		April	04
		May	05
		June	06
		July	07
		August	08
		September	09
		October	10
		November	11
		December	12
		Unknown or not stated	blank or 99
Day	48-49	01-31 Unknown or not stated	blank or 99
Year	50-53	1850 - 20xx Blank if unknown
4. Father's Surname	54-71	Alpha, left justified or blank if unknown		Follow the coding instructions for 'surnames' as specified in EXHIBIT 3. For females the provision of FATHER?S SURNAME is encouraged. For males FATHER'S SURNAME is necessary only when it differs from LAST NAME.
5. Age at Death				Code the ACTUAL age at death if it is already known. An estimated age at death may be used only when deaths for one year are being searched. The 'unit' field identifies the type of units for which age at death is measured. Example: Age 65 years Unit = 0 Number of Units = 65 Example: Age 105 years Unit = 1 Number of units = 05 Example: Age 8 months Unit = 2 Number of units =08 Example: Age unknown Unit = blank or 9 Number of units = blank or 99
Unit	72	Year: less than 100	0
		Years: 100 or more	1
		Months	2
		Weeks	3
		Days	4
		Hours	5
		Minutes	6
		Age unknown	blank or 9
Number of Units	73-74	Enter age	01-99
		Age unknown	blank or 99
6. Sex	75	Male	1 or M
		Female	2 or F
		Unknown	blank or 9
7. Race	76	White	1*	* White (includes Mexican, Puerto Rican and all Caucasian) * Indian (includes American, Alaskan, Canadian, or Mexican Indian, Eskimo, and Aleut) * Hawaiian (includes part Hawaiian) * Other nonwhite (includes Cajun and Creole)
		Black	2
		Indian	3*
		Chinese	4
		Japanese	5
		Hawaiian	6*
		Other nonwhite	7*
		Filipino	8
		Other Asian or Pacific Islander	0
		Unknown, not stated, or not classifiable	blank or 9
8. Marital Status	77	Never married/single	1*	* Other Entries Annulled 1 Separated 2 Common law marriage 2
		Married	2*
		Widowed	3
		Divorced	4
		Unknown	blank or 9
9. State of Residence	78-79	ALPHA and/or NUMERIC codes		See EXHIBIT 4 for the ALPHA and/or NUMERIC codes which may be used. Insert last known STATE of residence. If provided by the NDI user it will be matched against the State of residence as reported on the death certificate.
		States	01-51
		Puerto Rico	52
		Virgin Islands	53
		Guam	54
		Canada	55
		Cuba	56
		Mexico	57
		Remainder of World	59
		Unknown	blank or 99
10. State of Birth	80-81	(Same code structure as 'State of Residence' above)		See EXHIBIT 4 for the ALPHA and/or NUMERIC codes which may be used.
11. Control or Sequence Number (OPTIONAL)	82-91	Any combination of ALPHA/NUMERIC If no numbers are assigned, leave this field BLANK.		This is an OPTIONAL field to assist NDI users in identifying the records they submit. Insert control (or ID) numbers assigned to persons in the study OR assign 'sequence numbers' based on the order that records appear on the file submitted to NCHS. If duplicate or alias records are submitted, a flag could be put at the end of the Control Number (e.g., D1, D2, DUP1, or DUP2). NOTE: NCHS will assign a sequence number whenever this field is left blank. The computer output will print the control or sequence number for each user record.
12. Optional User Data	92-97	Any combination of ALPHA/NUMBERIC If this field is not used, leave it BLANK		This OPTIONAL field may be used for any additional information on study subjects. Examples of possible uses are: Date or year of last contact (e.g., 011584 or just 1984) To flag TEST RECORDS of known decedents (e.g., D or DEAD). Coded information to identify special subgroups of study subjects To flag DUPLICATE or ALIAS records The NDI computer output will contain whatever the user decides to include in this field.
13. Blank Field	98-100

 

Exhibit 3: Coding Instructions for Names

 

Surnames (last name and father's surname):

1. If the entire surname will not fit in the 20 position field, truncate it.
2. If the surname has a space or apostrophe following a prefix, such as Van Braun, Mac Pherson, O'Toole, or O'Mally, the NDI edit program will remove the space and the apostrophe between the prefix and the name.
3. If more than one surname is given, separated by a space or hyphen, type each name in the surname field. The NDI edit program will remove the space or the hyphen.

4. If a subject's full name appears to contain a MAIDEN name (for example, Jane Karen SMITH-Lee or Jane SMITH Lee), it is important for the maiden name also to be entered separately in the FATHER'S SURNAME field to enhance the possibility of a match. Listed below are suggestions of how user records may be prepared to cover the two different situations:

   • Example: Jane Karen SMITH-Lee
     Key-First name: JANE
     Middle initial: K
     Last name: SMITH-LEE
     Father's surname: SMITH
   • Example: Jane SMITH Lee Key-First name: JANE
     Middle initial: S
     Last name: LEE
     Father's surname: SMITH
5. If more than one surname is given and you are uncertain as to which surname to put in the last name field, you should consider the merits of creating a duplicate or alias record(s), one record for each surname. This may enhance the effectiveness of the NDI file search, especially for records without Social Security numbers. You may want to flag such duplicate records by inserting codes of your own choosing in either the control number field (positions 82-91) or the optional user data field (positions 92-97).  NOTE: You are not charged for duplicate or alias records; however, please report them on your NDI Transmittal Form.
6. Suffixes or generational identifiers such as II, III, Jr., or Sr. will be removed by the NDI edit program.
7. For names such as Sister Mary Lawrence, enter LAWRENCE as the last name, SISTER MARY as the first name, and a BLANK for middle initial.

 

First names and middle initials:

1. If the entire first name will not fit in the field, truncate it.

2. If two first names and a middle name are given, type both first given names (with or without a space between each name) in the first name field and type the middle initial in the middle initial field (truncate).

   • Example: MARY ANN LOUISE Jones
     Key-First name: MARY ANN
     Middle initial: L
   • Example: MARY ANN Jones
     (Treat ANN as the middle name unless your records Indicate that ANN is part of the first name.)
     Key-First name: MARY
     Middle initial: A
3. If a person (a) goes by two distinctly different first names, (b) has a first name and a nick name, or (c) uses the shortened form of a presumed legal name (for example, Bob for Robert, Liz for Elizabeth, Ben for Benjamin) you should consider the merits of creating duplicate or alias record(s), one record for each first name. This may enhance the matching effectiveness of the NDI file search, especially for records without Social Security numbers. You may want to flag such duplicate records by inserting codes of your own choosing in either the control number field (positions 82-91) or the optional user data field (positions 92-97).  NOTE: You are not charged for duplicate or alias records; however, please report them on your NDI Transmittal Form.
4. If entries have a first initial and a middle name, enter an initial for the first name and an initial for middle name.
5. If entries have multiple middle names or initials enter only the first initial (for example, Robert M.L. Jones: type 'M' as the middle initial and drop the 'L'.
6. For infant deaths, names such as 'Baby Girl' Jones should be entered as Baby Girl for first name and Jones for last name.

 

 

Exhibit 4: State (or Foreign Country) of Residence, Birth and Death

 

State	Alpha Code	Numeric Code
Alabama	AL	01
Alaska	AK	02
Arizona	AZ	03
Arkansas	AR	04
California	CA	05
Colorado	CO	06
Connecticut	CT	07
Delaware	DE	08
District of Columbia	DC	09
Florida	FL	10
Georgia	GA	11
Hawaii	HI	12
Idaho	ID	13
Illinois	IL	14
Indiana	IN	15
Iowa	IA	16
Kansas	KS	17
Kentucky	KY	18
Louisiana	LA	19
Maine	ME	20
Maryland	MD	21
Massachusetts	MA	22
Michigan	MI	23
Minnesota	MN	24
Mississippi	MS	25
Missouri	MO	26
Montana	MT	27
Nebraska	NE	28
Nevada	NV	29
New Hampshire	NH	30
New Jersey	NJ	31
New Mexico	NM	32
New York	NY	33
North Carolina	NC	34
North Dakota	ND	35
Ohio	OH	36
Oklahoma	OK	37
Oregon	OR	38
Pennsylvania	PA	39
Rhode Island	RI	40
South Carolina	SC	41
South Dakota	SD	42
Tennessee	TN	43
Texas	TX	44
Utah	UT	45
Vermont	VT	46
Virginia	VA	47
Washington	WA	48
West Virginia	WV	49
Wisconsin	WI	50
Wyoming	WY	51
Puerto Rico	PR	52
Virgin Islands	VI	53
Guam	GU	54
Canada	CN	55
Cuba	CU	56
Mexico	MX	57
Remainder of World	RW	59
Unknown		99