Uniform Data Set version 4
UDSv4 - Template

United States

Reference ID

USDv4

Producer(s)

National Alzheimer’s Coordinating Center (NACC) and the NIA-funded ADRC network

Collections

Clinical Trial

Metadata

DDI/XML JSON

Created on

Jul 02, 2026

Last modified

Jul 07, 2026

Page views

12107

25. Principal referral source (refersc)

Data file: UDSv4TemplateForXMLD_2026-04-14_0731.REDCap.xml

Overview

Valid: 58

Range: -

Format:

Questions and instructions

Question pretext

[packet]='I' OR [packet]='I4'

Categories

Value	Category	Cases
1	Self	4	6.9%
2	Non-professional personal contact who is not a current or previous ADRC participant (e.g., spouse/partner, relative, friend, coworker)Non-professional personal contact who is not a current or previous ADRC participant (e.g., spouse/partner, relative, friend, coworker)	9	15.5%
3	Current or previous ADRC participant	6	10.3%
4	ADRC clinician, staff, or investigator	10	17.2%
5	Non-ADRC healthcare professional (e.g., clinician, nurse, social worker)Non-ADRC healthcare professional (e.g., clinician, nurse, social worker)	10	17.2%
6	Other research study clinician/staff/investigator (non-ADRC; e.g., ADNI, Women's Health Initiative, LEADS, ALL-FTD)Other research study clinician/staff/investigator (non-ADRC; e.g., ADNI, Women's Health Initiative, LEADS, ALL-FTD)	4	6.9%
8	Other	10	17.2%
9	Unknown	5	8.6%

Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.

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