Sunday, April 5, 2009

Introduction to offerings of SAS Software for Clinical Programming

The SAS System developed by SAS Institute had its first release in 1976 which was referred to as the statistical analysis system. During its early releases, it was a relatively small software package which provided statistical tools for performing regression or analysis of variance. This was useful for many academics and industries but became particularly popular within the pharmaceutical industry.

The SAS System is now no longer an acronym but has grown to have many different offerings which this chapter will explore. There are modules which are used in other industries but tools which are used within the biopharmaceutical industry will be explored in greater detail.

Classic SAS
There has been an explosion of new software from SAS Institute within the last few years. There are even new solutions developed specifically for the pharmaceutical industry such as SAS Drug Development or SAS Business Intelligence enterprise solutions. Even though there are many new software solutions provided to work with the powerful computing ever changing computing environment, the core foundation of the base SAS system has remained. The foundation class of software or commonly referred to as “base” SAS has its core based on the same programming language which Anthony Barr and James Goodnight developed in the seventies. This “classic” version of the SAS system continues to function within the larger suite of offerings from SAS. Even among the large array of new software, backward compatibility is maintained. This means that the same SAS program that ran in the 1976 will execute in the latest versions of SAS. All the new additions to the system work together as building blocks to meet the demands of the complex biopharmaceutical industry of today, but it is stayed true to its original humble beginnings in the classic version of SAS.

The way SAS is most commonly used in the pharmaceutical industry is process SAS program to produce analysis files or reports. This is accomplished by submitting the programs in either in batch or interactive mode. The batch mode can be access through the operating system either through the command line or selecting the program from a file manager such was Windows Explorer within the Windows operating system. In this case, the selection can be made through a menu by right mouse clicking on the program file. The user can then choose several options from the menu including the ability to batch submit.

The interactive mode presents the program in a “display manager” which displays the program in an editor with options to view the log and related output. There are more options for interactive exploration of data and to perform ad hoc analysis with the use of the inactive SAS tools as compared to the batch method. The engine which process the logic of the SAS program function as the core of the SAS system. In either case of batch or interactive, both methods use the base SAS engine which compiles and executes the SAS logic stored in a script or program in a text file. Although the newer Business Intelligence (BI) architecture augments this approach slightly and refers to the program as a stored process. In the various ways that users interact with SAS, then program script remains the most common way that users store their business logic which then interacts with the SAS system.

Within the base SAS System or Foundation SAS, there are two constructs that distinguishes SAS from most other programming languages. This includes the data step and SAS procedures. Data step is used to manipulate and transform the data from “source data” into a format used for analysis, also commonly referred to as an analysis files. The SAS procedures or PROCs are used to perform analysis upon the datasets and generate reports. These two constructs of the SAS programming language covers most of what is done to clinical trials data in preparation for a submission to regulatory agencies for the purpose of approving drug and medical devices. SAS is also used in other areas of clinical research, but the majority of its usages is primarily within the area of data analysis for drug safety and efficacy.

more to come in thbe book I am working on "Becoming a SAS Programmer in Pharmaceutical Industry"...

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