Introduction
This article was written to explain why there are so many Analysis Data Model (ADaM) documents and to help the ADaM user see how they have been designed to work together.
History
The CDISC ADaM team’s approach to standards development has been to break the work into small, cohesive chunks, which can be developed by sub-teams and released as each is ready. While this has expedited development, it has also resulted in the production of a myriad of ADaM documents that can be a struggle for a new ADaM user to understand.
For example, the ADaM Implementation Guide (ADaMIG) contains details about standard structures Subject-Level Analysis Dataset (ADSL) and Basic Data Structure (BDS), but you have to go to a separate Occurrent Data Structure (OCCDS) document for details about that structure. That’s because the ADSL and BDS structures have been around since 2009, but OCCDS didn’t get formalized until 2016. Instead of adding OCCDS to the ADaMIG, the ADaM team created a separate document to describe it.
Release Packages
To combat confusion about which ADaM documents are to be used with each other, the ADaM team has created “Release Packages”, with one zip file per version of ADaMIG. Each zip file contains all the ADaM documents that are intended to be used with that specific ADaMIG. For example, the ADaMIG v1.3 Release Package contains the following documents:
- ADaM v2.1 (17-Dec-2009)
- Important Considerations When Using ADaM v2.1 (29-Nov-2021)
- ADaM Implementation Guide v1.3 (29-Nov-2021)
- ADaM Structure for Occurrence Data Implementation Guide v1.1 (29-Nov-2021)
- ADaM Implementation Guide for Non-compartmental Analysis Input Data v1.0 (29-Nov-2021)
- ADaM Implementation Guide for Medical Devices v1.0 (29-Nov-2021)
- ADaM Conformance Rules v4.0 (29-Nov-2021)
There is also a similar release package for ADaMIG v1.2, v1.1, and v1.0, each containing a slightly different set of documents.
Important Considerations Document
One document included with all of the release packages is a short PDF titled “Important Considerations When Using ADaM v2.1”. This document attempts to deal with the shortcomings of the ADaM model document, which was released in 2009. It redirects the reader to reference other more recent CDISC documents for details on ADaM Classes, Subclasses, and Metadata examples.
Be sure to read this document before using any content in ADaM v2.1.
Relationship Chart
There is a handy chart found in section 1.3 of ADaMIG v1.1 and later, showing which other ADaM and ADaM-related documents are applicable to which version of each ADaMIG. Table 1 summarizes content from the chart that is found in ADaMIG v1.3, showing each version of the ADaMIG in a column, and all the other ADaM documents as rows. Read down the column of the ADaMIG you are going to use, to see which other documents are applicable.
Table 1: Other CDISC Documents and Their Applicability to ADaMIG Versions
| Document | ADaMIG v1.0 | ADaMIG v1.1 | ADaMIG v1.2 | ADaMIG v1.3 |
|---|---|---|---|---|
| Analysis Data Model | Foundational doc for ADaMIG v1.0 | Applicable | Applicable | Applicable |
| ADaM OCCDS IG v1.1 | Not written for ADaMIG v1.0 | Applicable | Applicable | Applicable |
| ADaM OCCDS v1.0 | Not written for ADaMIG v1.0 | Written for ADaMIG v1.1 | Applicable | Applicable |
| ADaM Data Structure for Adverse Event Analysis v1.0 | Written for ADaMIG v1.0 | Superseded by OCCDS v1.0 | Superseded by OCCDS v1.0 | Superseded by OCCDS v1.0 |
| ADaMIG for Non-compartmental Analysis (ADNCA) v1.0 | Not written for ADaMIG v1.0 | Applicable | Applicable | Applicable |
| ADaMIG for Medical Devices (ADaMIG-MD) v1.0 | Applicable | Applicable | Applicable | Applicable |
| ADaM Conformance Rules v4.0 | Applicable | Applicable | Applicable | Applicable |
| The ADaM BDS for Time-to-Event Analyses v1.0 | Written for ADaMIG v1.0 | Applicable | Applicable | Applicable |
| ADaM Statistical Examples v1.0 | Written for ADaMIG v1.0 | Applicable | Applicable | Applicable |
| Define-XML v2.0 | Applicable | Applicable | Applicable | Applicable |
| ARM Specification for Define-XML Version 2 v1.0 | Applicable | Applicable | Applicable | Applicable |
Notice that many of the documents designated as “Applicable” in the ADaMIG column are included in that ADaMIG Release Package. Don’t use any combination that includes text “Superseded by”. Be cautious of using any combination that incudes text “Not written for”.
Applying the ADaMIG with other Documents
Choosing Which ADaMIG and Define-XML to Use
Before trying to determine anything else, first decide which version of ADaMIG and Define-XML you will use. This choice is often made by considering who will be using the data, such as a regulatory agency. If submitting to a regulatory agency, review their current Data Standards Catalog to determine which version(s) of the ADaMIG can be used. US FDA and Japan PMDA catalogs can be found at:
Consider using the most current ADaMIG, regardless of whether the agency will officially accept it. Newer versions of the ADaMIG are very backward-compatible, meaning a study can make use of all the new variables in the latest ADaMIG version, just call it an older version for submission and when using any conformance tools. The handful of minor issues that might crop up due to using the later IG, such as a minor variable label change, are easily explained in an Analysis Data Reviewer’s Guide (ADRG) and often worth being able to use all the latest content.
Once you have determined the ADaMIG version, look at Table 1 to determine which other documents you can use. You can also download the full ADaMIG release package from the CDISC ADaM website, which contains the full set of documents.
Standards vs. Examples
Some of the ADaM documents are standards, detailing what can and can’t be done. These include the model itself and the IGs.
Other ADaM documents contain strictly examples. These include the ADaM BDS for Time-to-Event Analysis and the ADaM Statistical Examples documents, which both show how to use the standard structures and variables outlined in the model and IGs. ADaM continues to develop examples documents, such as how to provide traceability and how to develop Oncology-specific datasets. ADaM examples documents are a great resource when trying to apply the model and IG in a specific setting. Some Therapeutic Area User Guides (TAUGs) also contain ADaM examples.
Examples are not standards, and you are not required to follow them. Use the ADaM examples for guidance and maybe a starting point when designing a dataset for a similar need. Always follow the fundamental principles of ADaM.
Handling Conflicts Across the Documents
Because there are so many ADaM documents, concepts described in one document may also appear in other documents. When these documents have different release dates, wording might be different across them. Pay attention to the release dates of each document, noting that older release dates will likely have some outdated content. Whenever you find conflicts across ADaM documents, use the content from the most recent document.
What to Expect in the Future
The ADaM team is planning to begin consolidating these multiple ADaM documents into a smaller set of documents. This consolidation should remove redundancy and help make the content more consistent. Until then, information will continue to be found spread across many separate documents.