CDISC ADaM 2.1

Purpose

The Analysis Data Model (ADaM) specifies the fundamental principles and standards to follow when creating analysis data sets and associated metadata. ADam supports efficient generation, replication, and review of analysis results. The design of analysis data sets is generally driven by the scientific and medical objectives of the clinical trial. A fundamental principle is that the structure and content of the analysis data sets must support clear, unambiguous communication of the scientific and statistical aspects of the clinical trial.
The purpose of ADaM is to provide a framework that enables analysis of the data. At the same time, ADaM enables reviewers and other recipients of the data to have a clear understanding of the data’s lineage from collection to analysis to results. Whereas ADaM is optimized to support data derivation and analysis, CDISC Study Data Tabulation Model (SDTM) is optimized to support data tabulation.

Release Date

CDISC ADaM Analysis Data Model, Final Version 2.1, December 17, 2009

Regulatory Basis

(Source: Submission of Data in CDISC Format to CBER, http://www.fda.gov/BiologicsBloodVaccines/DevelopmentApprovalProcess/ucm209137.htm, page updated: January 6, 2011)
Effective December 15, 2010, SDTM and ADaM are being accepted for all BLA submissions. (Source: Study Data Specifications, Version 1.5.1, January 4, 2010)
Before submission, sponsors should contact the appropriate center’s review division to determine the division’s analysis data set needs. The CDISC ADaM standard for analysis data sets ( http://www.cdisc.org/adam) can be used if it is acceptable to the review division.
To determine how to create ADaM analysis data sets for submission to CDER, sponsors should refer to the following three documents:
You should comply with the Analysis Data Model Implementation Guide. Any specific questions about these documents should be discussed with the review division.

CDISC ADaM 2.1 Reference Standard

Section 2.1 of the Analysis Data Model Implementation Guide provides the fundamental principles of the CDISC ADaM model.
  • Analysis data sets and associated metadata must clearly and unambiguously communicate the content and source of the data sets supporting the statistical analyses performed in a clinical study.
  • Analysis data sets and associated metadata must provide traceability to enable an understanding of where an analysis value came from.
  • Analysis data sets must be readily usable with commonly available software tools.
  • Analysis data sets must be associated with metadata to facilitate clear and unambiguous communication. Ideally, the metadata is machine-readable.
  • Analysis data sets should have a structure and content that enable statistical analyses to be performed with minimal programming. Such data sets are described as analysis-ready.
Implementation of the CDISC ADaM 2.1 reference standard in the SAS Clinical Standards Toolkit supports each of these principles.
The number and structure of analysis data sets are highly dependent on the type of study, the study objectives as defined in the statistical analysis plan, and discussions with the reviewing authority. ADaM data sets incorporate derived and collected data that permit analysis with little or no additional programming. Data can be from various SDTM domains, other ADaM data sets, or any combination thereof.
As initially released, the CDISC ADaM 2.1 reference standard supports two types of analysis data set structures:
  • The subject-level analysis data set (ADSL) provides descriptive information about subjects, such as study disposition, demographic, and baseline characteristics. The ADSL is the primary source for subject-level variables included in other analysis data sets, such as population flags and treatment variables. There is only one ADSL per study, and the ADSL and its related metadata are required in each CDISC-based submission of data from a clinical trial, even if no other analysis data sets are submitted.
  • The ADaM Basic Data Structure (BDS) is used for the majority of ADaM data sets, regardless of the therapeutic area or type of analysis. Each BDS data set contains one or more records per subject and analysis parameter. The structure of some BDS data sets might include an analysis time point. A record in a BDS analysis data set can represent an observed, derived, or imputed value required for analysis. Each BDS data set contains a core set of variables that describe the analysis parameter and the value being analyzed. A data value can be derived from any source file, including any combination of SDTM and ADaM data sets.
The Analysis Data Model identifies four types of metadata that are captured and supported by the SAS Clinical Standards Toolkit.
ADaM Metadata Types and SAS Clinical Standards Toolkit Locations
ADaM Metadata Type
SAS Clinical Standards Toolkit Location
Analysis data set metadata
reference_tables.sas7bdat
Analysis variable metadata
reference_columns.sas7bdat
Analysis parameter-value-level metadata
reference_columns.sas7bdat (parameterid column)
Analysis results metadata
Derivable from reference_columns.sas7bdat (where table=’RESULTS’)
Version 1.0 of the Analysis Data Model Implementation Guide (ADaMIG) defines a common set of ADSL and BDS columns that can be used as templates for any ADaM analysis data set. These columns are defined in the SAS Clinical Standards Toolkit reference_tables and reference_columns data sets. These SAS Clinical Standards Toolkit data sets contain a metadata representation of the analysis results metadata. Empty ADSL, BDS, and analysis results data sets can be derived from the SAS Clinical Standards Toolkit global standards library using the utility macro cst_createTablesForDataStandard.
To see the SAS Clinical Standards Toolkit metadata that is available, Sample Reference_Tables Record (CDISC ADaM 2.1)andSample Reference_Columns Record (CDISC ADaM 2.1) provide a sample record from the reference_tables and reference_columns data sets, respectively. These data sets are found in the standard metadata folder.
Sample Reference_Tables Record (CDISC ADaM 2.1)
Column Name
Column Value
sasref
REFDATA
table
ADSL
label
Subject-Level Analysis Dataset
class
ADSL
xmlpath
adsl.xpt
xmltitle
structure
One record per subject
purpose
Analysis
keys
USUBJID
state
Final
date
2009-12-17
standard
CDISC-ADAM
standardversion
2.1
standardref
comment
Subject disposition, demographic, and baseline characteristics
documentation
SAP, <deriving SAS code>
Sample Reference_Columns Record (CDISC ADaM 2.1)
Column Name
Column Value
sasref
REFDATA
table
BDS
column
TRTP
label
Planned Treatment
order
5
type
C
length
40
displayformat
xmldatatype
text
xmlcodelist
core
Req
role
TreatmentBDS
term
parameter
sourcederivation
qualifiers
standard
CDISC-ADAM
standardversion
2.1
standardref
comment
TRTP is a record-level identifier that represents the planned treatment attributed to a record for analysis purposes. TRTP indicates how treatment varies by record within a subject and enables analysis of crossover and other designs. TRTxxxxP (copied from ADSL) may also be needed for some analysis purposes, and may be useful for traceability and to provide context.
The SAS Clinical Standards Toolkit CDISC ADaM reference standard also provides metadata and code to validate the structure and content of the ADaM analysis data sets.
To enable validation, supplemental files supporting ADaM validation processes include these SAS Clinical Standards Toolkit global standards library files:
  • The Validation Master data set in the validation/control folder contains the superset of checks validating the structure and content of each analysis data set. These checks are based on version 1.1 of the CDISC ADaM Validation Checks as prepared by the CDISC ADaM team.
  • The Messages data set in the messages folder provides error messaging for all Validation Master checks.
  • SAS code in the macros folder provides code that is specific to ADaM that augments code that is provided in the primary SAS Clinical Standards Toolkit autocall library (!sasroot/cstframework/sasmacro).
These supplemental files, in whole or in part, define the SAS Clinical Standards Toolkit CDISC ADaM reference standard.