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NESUG 2011 Publication

https://lexjansen.com/nesug/nesug11/ph/ph08.pdf

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SAS Interview Questions and Answers: CDISC, SDTM and ADAM etc

- September 23, 2008

1) What do you know about CDISC and its standards? CDISC stands for Clinical Data Interchange Standards Consortium and it is developed keeping in mind to bring great deal of efficiency in the entire drug development process. CDISC brings efficiency to the entire drug development process by improving the data quality and speed-up the whole drug development process and to do that CDISC developed a series of standards, which include Operation data Model (ODM), Study data Tabulation Model (SDTM) and the Analysis Data Model ADaM ). 2) Why people these days are more talking about CDSIC and what advantages it brings to the Pharmaceutical Industry? A) Generally speaking, Only about 30% of programming time is used to generate statistical results with SAS®, and the rest of programming time is used to familiarize data structure, check data accuracy, and tabulate/list raw data and statistical results into certain formats. This non-statistical programming time will be significantly reduced...

SDTM Programming Interview Questions and Answers

- August 31, 2024

SDTM Programming Interview Questions and Answers 1. What is SDTM, and why is it important in clinical trials? Answer: SDTM (Study Data Tabulation Model) is a standardized format for organizing and submitting clinical trial data to regulatory authorities, such as the FDA. It is important because it ensures that data is structured consistently across studies, facilitating data review, analysis, and submission. 2. What are the key components of an SDTM dataset? Answer: The key components of an SDTM dataset include: Domains: Specific datasets like DM (Demographics), AE (Adverse Events), LB (Laboratory), etc. Variables: Each domain has standard variables such as USUBJID (Unique Subject Identifier), DOMAIN, VISIT, and others. Value-Level Metadata: Defines the structure and content of the variables. Controlled Terminology: Standard terms and codes used in SDTM datasets. 3. What is the purpose of the DM (Demographics) domain in SDTM? Answer: The DM domain in SDTM provi...

SAS Clinical Interview QUESTIONS and ANSWERS

- November 03, 2008

SAS Clinical Interview Questions and Answers SAS Clinical Interview Questions and Answers Here is a list of common SAS clinical interview questions along with example answers and explanations to help you prepare for your next interview. 1. What is SAS? SAS stands for Statistical Analysis System. It is a software suite used for advanced analytics, business intelligence, data management, and predictive analytics. It is widely used in clinical trials for analyzing clinical data. 2. What are the phases of clinical trials? The phases of clinical trials include: Phase I: Tests safety and dosage with a small group of healthy volunteers. Phase II: Tests efficacy and side effects with a larger group of patients. Phase III: Confirms effectiveness, monitors side effects, and compares with other treatments in larger patient groups. Phase IV: Conducts post-marketing studies to gather additional inf...

Resolving the SAS EG Transcoding Error

- November 19, 2024

Resolving the SAS EG Transcoding Error Addressing the "Character Data Lost During Transcoding" Issue in SAS EG Author: Sarath Date: November 19, 2024 Introduction While working in SAS Enterprise Guide (SAS EG), you may encounter the error: "Some character data was lost during transcoding in the dataset." This issue typically arises when character data contains unsupported characters or is truncated due to insufficient column lengths. In this blog post, we'll explore the root causes and provide step-by-step solutions. Common Causes Unsupported Characters: The data contains special or non-ASCII characters not representable in the session encoding. Truncation: Character variables are too short to store the full data, leading to loss of information. ...

Common P21 SDTM Compliance Issues and How to Resolve Them

- December 06, 2024

Common P21 SDTM Compliance Issues and How to Resolve Them Common P21 SDTM Compliance Issues and How to Resolve Them By Sarath Annapareddy Introduction Pinnacle 21 (P21) is a cornerstone for validating SDTM datasets against CDISC standards. Its checks ensure compliance with regulatory requirements set by the FDA, PMDA, and other authorities. However, resolving the issues flagged by P21 can be challenging, especially for beginners. This post dives into common P21 compliance issues and provides actionable solutions with examples. 1. Missing or Invalid Controlled Terminology Issue: P21 flags variables like LBTESTCD or SEX as non-compliant with CDISC Controlled Terminology (CT). This happens when values in your datasets are o...

SDTM IG 3.4: SR, OE, LB Domain Expansion, and Revised SUPPDS Assumptions

- April 09, 2026

SDTM IG 3.4: SR, OE, LB Expansion, and Revised SUPPDS Assumptions | StudySAS Blog SDTM IG 3.4 was published by CDISC in July 2022 alongside SDTM v2.0. [1] This post focuses on what actually changes programming and submission behavior — written for SDTM programmers and submission leads. If you have been working from 3.2 or 3.3, several of these changes will require updates to domain routing logic, controlled terminology mappings, Define.xml metadata, and SUPPDS population rules that have been stable in company standards for years. This post examines four areas where working programmers face concrete re-mapping decisions: the SR domain and how the IS scope expansion in 3.4 redraws its boundaries, the OE domain as the post-MO home for ophthalmic data, the restructured LB with confirmed new variables and a substantially narrowed scope, and the SUPPDS assumptions v3.4 quietly rewrote. One terminology correction before we start. Several posts and internal notes referenc...

Understanding EC vs. EX Domains in SDTM: When to Use Each

- September 10, 2024

Understanding EC vs. EX Domains in SDTM: When to Use Each Understanding EC vs. EX Domains in SDTM: When to Use Each In SDTM, the EC (Exposure as Collected) and EX (Exposure) domains are both used to capture data related to drug or therapy exposure, but they serve different purposes depending on how the exposure data is collected and whether the study is blinded or unblinded. Key Updates from PharmaSUG Papers: PharmaSUG 2017 Paper DS08 introduces the historical context of the EC domain, which was established in SDTMIG v3.2 to support the EX domain by providing detailed traceability for exposure data. EC helps capture deviations, titrations, and other variations from planned dosing, especially when the collected data doesn't match protocol-specified dosing. PharmaSUG 2022 Paper DS121 emphasizes the importance of capturing dose modifications using the EC domain, which often occurs in oncology trials. By utilizing EC, sponsors can accurate...

7 Mistakes in LB Unit Conversion That Still Show Up in SDTM

- April 09, 2026

7 Mistakes in LB Unit Conversion That Still Show Up in SDTM | StudySAS LB unit conversion is not hard to understand. The variable definitions are clear. The model is well-documented. And yet unit-related problems remain among the most common issues in SDTM submissions — not because teams do not know the rules, but because the failures are quiet. Nothing crashes. The dataset looks valid. Pinnacle 21 returns a clean report. Then a reviewer runs a simple cross-tabulation and finds creatinine flagged HIGH at a value that belongs well within the normal range — because the reference range was never converted to match the standard unit. This post is a close look at seven implementation mistakes, each with enough context and worked examples to make the failure mode visible before it reaches a submission. LBORRES is what was collected. Verbatim. Untouched. LBSTRES* is the standardized representation. One unit per test. LBSTNR* must follow the same unit system as LBSTRES*. T...

Developing the DC (Demographics as Collected) SDTM Domain

- September 01, 2024

Developing the DC (Demographics as Collected) SDTM Domain Developing the DC (Demographics as Collected) SDTM Domain: Tips, Techniques, Challenges, and Best Practices Introduction The DC (Demographics as Collected) domain is a specialized SDTM (Study Data Tabulation Model) domain designed to capture demographic data as it was originally collected in clinical trials. This domain is particularly valuable in studies that involve multiple screenings or re-enrollments, where maintaining the integrity of the collected data is crucial. Unlike the DM (Demographics) domain, which provides a standardized summary of demographic data, the DC domain preserves the raw, unstandardized data, ensuring accurate data representation. This article delves into the key aspects of developing the DC domain, including the challenges, best practices, and the critical differences between the DC and DM domains. We also integrate insights from industry pa...

Studyday calculation ( --DY Variable in SDTM)

- January 12, 2013

USE OF THE “STUDY DAY” VARIABLES The permissible Study Day variables (--DY, --STDY, and --ENDY) describe the relative day of the observation starting with the reference date as Day 1. They are determined by comparing the date portion of the respective date/time variables (--DTC, --STDTC, and --ENDTC) to the date portion of the Subject Reference Start Date (RFSTDTC from the Demographics domain). The Subject Reference Start Date (RFSTDTC) is designated as Study Day 1. The Study Day value is incremented by 1 for each date following RFSTDTC. Dates prior to RFSTDTC are decremented by 1, with the date preceding RFSTDTC designated as Study Day -1 (there is no Study Day 0). This algorithm for determining Study Day is consistent with how people typically describe sequential days relative to a fixed reference point, but creates problems if used for mathematical calculations because it does not allow for a Day 0. As such, Study Day is not suited for use in subsequent numerical computations...