2017 Fixity Survey Report: An NDSA Report

EXECUTIVE SUMMARY

Fixity checking, or the practice of algorithmically reviewing digital content to insure that it
has not changed over time, is a complex but essential aspect in digital preservation
management. To date, there have been no broadly established best practices surrounding
fixity checking, perhaps largely due to the wide variety of digital preservation systems and
solutions employed by cultural heritage organizations. In an attempt to understand the
common practices that exist for fixity checking, as well as the challenges institutions face
when implementing a fixity check routine, the National Digital Stewardship Alliance (NDSA)
Fixity Working Group developed and published a survey on fixity practices in fall of 2017. A
total of 164 survey responses were recorded, of which 89 completed surveys were used in
results analysis. Several themes emerged from the survey results:
   ● The vast majority of respondents are fixity checking their content or are planning to
      do so.
   ● Fixity checking at specific times, such as to establish an initial baseline fixity value
      after acquiring content and rechecking fixity values after data transfers, is
      recognized as good practice.
   ● Fixity checking practices varied widely based on the organization, the amount of
      resources (human and technical) available, the types of software and hardware
      implemented, and the size of the data corpus to be preserved.

The most common challenges associated with implementing a fixity check routine appear
to be related to a lack of resources available to set up and maintain the infrastructure
necessary to run fixity checks.