NACC quality assurance quick links:

 • Monthly and quarterly QA reports

 • Electronic error and alert checks

 • The UDS data-collection protocol

 • Contact the Quality Assurance Group


Overview of the NACC QA process

NACC builds quality assurance (QA) and quality control (QC) measures into each step of the data-collection process, and NACC’s QA Group has instituted a rigorous QA procedure that is part of a continual, cyclical process. Throughout this process:

  • • We welcome feedback about data quality from researchers using our data, and we investigate all issues brought to our attention.
  • • We frequently review the database to detect data inconsistencies that need correction or verification.
  • • We use the data in our own research, which increases our understanding of the details of the data and helps us uncover problems.
  • • We are in regular contact with the ADCs by phone and email, providing guidance and answering questions about QA/QC issues.

Quality assurance procedures at NACC

BEFORE NACC ACCEPTS DATA, the QA Group works to:

  • • Review NACC’s new data-collection forms to ensure that they are scientifically and clinically logical and consistent, that they capture the intended scientific purpose, and that they provide all of the necessary options to reduce ambiguity during form completion;
  • • Review and approve electronic data-entry forms developed by ADCs to ensure that the data they collect will be exactly the same as data collected using NACC’s paper forms;
  • • Provide the ADCs with standardized documentation — such as forms, coding documents (Data Element Dictionary and Data Template), clinical diagnostic criteria, and detailed scoring instructions for neuropsychological tests — to ensure that all Centers are coding their collected data in a consistent manner;
  • • Provide training as needed to ADCs on data collection and data submission; and
  • • Program electronic error and alert checks to prevent questionable data from entering the database and being used by researchers.


  • • Performs regular monitoring of data submissions by the ADCs to ensure that the data conform to the UDS data-collection protocol;
  • • Monitors monthly and quarterly reports to the ADCs summarizing their submissions and identifying trends; and
  • • Remains flexible in the ways in which data corrections are processed and verified by the ADCs, in order to ease the burden on the Centers and decrease the time data are held in the QA process.

BEFORE SENDING DATA TO INVESTIGATORS, the Research Support Group and QA Group work together to:

  • • Check the data sets to minimize data-quality concerns, and
  • • Advise researchers, via phone and email, about appropriate use of the data through standardized and customized documentation.

Please contact us for more information about NACC’s QA/QC efforts.