About the Bit List

What is the Bit List?

The Bit List is a free, open and community-sourced advocacy tool developed by the Digital Preservation Coalition (DPC) to highlight digital materials at risk of loss. Drawing on the experience of the global digital preservation community, the Bit List was first released in 2017 and is reviewed every two years with updates in between. It identifies a wide range of endangered digital content across diverse organizational settings. These risks may stem from technological obsolescence, media decay, or broader issues such as accountability, policy, and business processes.

The list is based on real-world experience from professionals who work to keep digital materials accessible over time. These experts come from various countries and sectors. The Bit List is not a top-down or theoretical project, and it does not serve political or commercial interests. Entries to the list are included because experienced professionals have faced challenges preserving them and believe they should be highlighted.

While the Bit List covers all types of digital materials, it does not include everything which is at risk—only those that the community has identified. If a digital material is not listed, this does not mean it is safe—just that it has not yet been reported. On the other hand, if a digital material is listed, it shows that some effort has been made to protect it. Most entries are broad and may overlap, which can affect how urgent the need for action is.

The Bit List serves three main purposes for three key audiences:

• As an advocacy tool, it aims to influence the technology sector and senior decision-makers by highlighting the urgent risks facing digital materials. It encourages informed, long-term investment in digital preservation.
• As a practical guide, it offers a simple roadmap for tackling preservation challenges. The Bit List invites all contributors to the digital preservation community to address the issues raised and recognizes progress toward solutions.
• As a current overview, it provides up-to-date guidance for the digital preservation community. As a resource, it aims to be especially helpful for newcomers and educators, while also supporting experienced professionals facing new challenges and those making the case for digital preservation within their organizations.

The Bit List offers a provisional commentary with the recognition that the extent of the digital domain, the complexity of the threats, and the sophistication of emerging solutions mean that no process could ever fully capture the risks and challenges faced by digital content around the world. It is published and reviewed with the understanding that new risks are continuously arising; every day and (inevitably) between editions of the Bit List. Members of the Bit List Council recognize that differences in emphasis and subtleties of local context may well have been overlooked, and that material changes may have occurred during the process.

The Bit List is designed to be collaborative, iterative and provisional. Thus, if readers are aware of significant digital collections that do not match up with any of the broad examples given but are at material risk, they are encouraged to draw these to the attention of the Bit List Council through the DPC’s Chief Community Officer. These will be reviewed in time for publication of the next scheduled comprehensive review of the Bit List. Where digital materials face an imminent extinction event before that, their evaluation may be accelerated and an addendum published to the Bit List in order to provide the timely, impartial and expert advocacy that may be required. Corrections, comments and nominations are welcome.

Using the Bit List

Accessing the List

In order to best support the advocacy endeavours of the digital preservation community, the Bit List is offered both as this online resource and a downloadable report (via this link), to facilitate the various ways in which its information is used.

Online, the Bit List provides a searchable set of entries and a means to browse the listing by category and risk classification, as well as offering packages of advocacy information for various organisation types and sectors.

The downloadable Bit List report contains observations about the context in which the entries have been reviewed, as well as recommendations and key messages for particular sets of actors and stakeholder groups. Within the report, entries are arranged first by threat then by risk classification. Individual entries are then presented in alphabetical order. A full index of entries is provided as an appendix to this report.

Interpreting the entries

In both formats, each entry contains the following information:

(1) Title – Each item on the list is given a short title to represent the digital material represented.

(2) Description – Each entry is described in general terms.

(3) Risk Classification – based on an evaluation by the Bit List Council, each entry is assigned a risk classification. This takes into consideration the imminence of action required to safeguard the material, the effort required to preserve the material and the inevitability of loss. The classifications assigned start at ‘Lower Risk’ and escalate to ‘Practically Extinct’ (see page XX for the full list of classifications and their definitions). In each case, the context in which the digital material exists, as well as the presence of aggravating factors, are used to guide the evaluation.

(4) Category – entries belong to broad categories to aid users with discovery and identification. Entries overlap; any given entry may appear under multiple categories depending on technology, resourcing or organizational contexts. These overlaps mean items may also indicate greater risk given the that actions to tackle the risks are potentially more complex.

(5) Examples – examples are illustrative not exhaustive and in many cases these examples are also broadly defined, representing many specific instances. The examples typically include specific submissions made in the open nomination process and examples arising from Council discussions.

(6) Imminence – One of the evaluation criteria, it invites nominators and the Bit List Council to consider how quickly you need to act to save this digital material? This indicator is rated 1 – 5, where 5 = Act immediately within 6 months; 4 = Around 12 months; 3 = Less than 3 years; 2 = Within 5 years; 1 = More than 5 years. 

(7) Effort to preserve - One of the evaluation criteria, it invites nominators and the Bit List Council to consider whether loss of this digital material could be avoided, and what the effort to preserve might be? This indicator is rated 1 – 5, where 5 = Inevitable; 4 = Loss seems likely; 3 = Major effort to fix; 2 = Small effort to fix; 1 = Entirely avoidable. 

(8) Hazards - Each entry includes examples of Hazards which amplify the risks to a digital object and relate to the broader threats which are faced by the digital object. Entries are linked by the threats they face. Recognizing that entries are very broadly defined, digital materials may be at more or less risk depending on local circumstances. Where associated threats have been identified, these appear at the foot of the Hazards section.

(9) Mitigations – each entry offers a set of Mitigations or good practice that would reduce the risk imposed by the Hazards and threats. These are also implied recommendations for addressing and reducing risks to be followed in the timescale indicated. In most cases, a fuller assessment is also suggested. By implication, the actions that would arise from such an assessment are not likely to be trivial.

(10) Bit List History – this section tracks the trajectory of the entry on the Bit List since its first nomination and includes commentary from the Bit List Council to help users understand the rationale behind evaluations and decisions made.

(11) Added to list – every two years, the Bit List Council calls for new nominations to the Bit List. The year that each entry was nominated and added to the list is displayed here.

(12) Trends - Each item notes the trend from the preceding and current year with commentary. There are three classes of trend relating to the risks to clarify their meaning, which are summarized below:

• Towards greater risk - where the Council has reason to believe preservation is becoming significantly harder than the previous year. This may not be sufficient to cause the entry to change risk classification but indicates movement within the risk classification.
• Material improvement - where the Council has reason to believe Trends towards reduced risk have accelerated. This may not be sufficient to cause the entry to change risk classification but indicates movement within the risk classification.
• No change - In every other case there is no change to the trend. This does not mean the trend has stopped but that the Council believe the trend has continued as reported last year.

(13) Last Review – detailed comments from the Bit List Council pertaining to the most recent review cycle have been included where available. Often these follow and incorporate details from previous review cycles where relevant, providing a historical account of the entry on the Bit List.

(14) Additional Information – where available and relevant, any further useful information pertaining to each entry is provided.

(15) Case studies and examples – where these have been offered by nominators or the Bit List Council, case studies and examples in support of the Bit List’s assessment of each entry are included. Where the community is aware of better or more current examples or case studies, they are invited to share these for inclusion in the Bit List.

(16) Keep me informed (online only) - this link offers a way to express your interest in a particular entry.