PubChem uses a "legacy" designation to give users the option to filter collections that are not regularly updated. This "legacy" designation applies to project/contributors that appear to no longer be active, as well as to their individual records. This designation helps PubChem users quickly identify records that may have out-of-date information and/or hyperlinks. Further introduction to this concept can be found in this PubChem blog post.
As an archive, PubChem accepts scientific data from contributors and maintains that data even if the contributing project is discontinued. While this helps ensure community access to the information lasts beyond the lifetime of a given scientific endeavor, the archival nature of PubChem does not allow anyone other than the data contributor to modify provided information. Therefore, some records in PubChem can persist with outdated (or incorrect) data. To help identify such cases, PubChem designates "legacy" contributors and their records. Please note that this does not mean that data identified as "legacy" is without value. Quite to the contrary, some legacy collections successfully collected valuable scientific data for the research community, and are simply no longer updating the information.
A "legacy" designation is arrived at via a semi-manual, semi-automated procedure. It involves aspects of examining contributor account information, individual records, and user reports. In general, the designation process follows these guidelines:
- Identify PubChem data collections with non-functioning web links (URLs).
- Identify PubChem data collections without *recent updates.
- Attempt to contact contributors meeting either of the two above criteria.
- If contact fails, attempt more general organization contacts.
- If repeated contact attempts fail, assign legacy status.
*PubChem wishes to minimize the number of legacy designated accounts and is eager to work with the contributor to update accounts. If, for example, an update is expected in the near term, that should satisfy the immediate need for update. Please note that a "legacy" designation can be removed at any time, when contact is reestablished and updates resume.
If a data contributor is designated as "legacy", all records deposited by the contributor are also designated as "legacy". While still searchable, these records clearly indicate that they are "legacy". Please note that "legacy" records are not shown in the "Chemical Vendors" section of Compound Summary pages. In addition, in the "Substances by Category" section of the Compound Summary page, "legacy" substance records are only found under "Legacy Depositors".
The way PubChem implements both manual and automated processes to ascertain a "legacy" indication will likely evolve over time. In addition, we are looking at the possibility of enabling users to separate out legacy records when searching and analyzing the database. Please refer back to this page for the latest information on this topic.