Clinical SAS Programmer Interview Question and Answers

Clinical SAS Programmer Interview Question and Answers


1. What are Macro libraries?

ANS: Macro libraries are the libraries, which stores all the macros required for developing TLG’s of the clinical trial. These are very are necessary in controlling and managing the macros. With the help of a %INCLUDE statement; the stored macros in the macro library can be automatically called.

2. Why do you use ODS?

ANS: ODS (Output Delivery System) normally used to make the output from the Tables, Listings and graphs looks pretty. ODS creates the outputs in html, pdf and rtf formats.

3. What are the graphs you created?

ANS: Survival estimate graphs.

4. How to generate statistics using Proc SQl?

ANS: Yes, we can generate the statistics like N, Mean, Median, Max, Min, STD & SUM using PROC SQL. But SQL procedure cannot calculate all the above statistics by default, as it is the case with PROC MEANS.

5. When to use Proc SQl?

ANS: The SQL procedure supports almost all the functions available in the DATA step for the creation of data as well as the manipulation of the data. When we compare the same result, obtained from SQL and with the Data step, PROC SQL requires less code and, more importantly it requires less time to execute the code

6. Which procedure is used to create reports?

ANS: Proc Report, proc Tabulate and Data _null_.

7. What is the difference between stratum and by statement in Proc Lifetest?

ANS: We specify a BY statement with PROC LIFETEST to obtain separate analyses on observations in groups defined by the BY variables.

8. Describe the phases of clinical trials?

ANS: These are the following four phases of the clinical trials:

Phase 1: Test a new drug or treatment to a small group of people (20-80) to evaluate its safety.

Phase 2: The experimental drug or treatment is given to a large group of people (100-300) to see that the drug is effective or not for that treatment.

Phase 3: The experimental drug or treatment is given to a large group of people (1000-3000) to see its effectiveness, monitor side effects and compare it to commonly used treatments.

Phase 4: The 4 phase study includes the post marketing studies including the drug’s risk, benefits etc.

9. What are the advantages of using SAS in clinical data management?

ANS: Less hardware is required and fewer personnel are required.

10. Describe SDTM?

ANS: CDISC’s Study Data Tabulation Model (SDTM) has been developed to standardize what is submitted to the FDA.

11. What is CRT?

ANS: Case Report Tabulation, whenever a pharmaceutical company is submitting an NDA, conpany has to send the CRT’s to the FDA.

12. What is annotated CRF?

ANS: Case report form, it’s a collection of the forms of all the patients in the trial.

13. Describe the validation procedure?

ANS: Validation procedure is used to check the output of the SAS program, generated by the source programmer. In this process validator write the program and generate the output

13. How would you perform the validation for the listing, which has 400 pages?

ANS: It is not possible to perform the validation for the listing having 400 pages manually. To do this, we convert the listing in data sets by using PROC RTF and then after that we can compare it by using PROC COMPARE.

14. How would you generate tables, listings and graphs?

ANS: We can generate the listings by using the PROC REPORT. Similarly we can create the tables by using PROC FREQ, PROC MEANS, and PROC TRANSPOSE and PROC REPORT. We would generate graph, using proc Gplot etc.

15. How would you submit the docs to FDA? Who will submit the docs?

ANS:  We can submit the docs to FDA by e-submission. Docs can be submitted to FDA using

16. What are the docs do you submit to FDA?

ANS: We submit ISS and ISE documents to FDA.

Define.pdf or define.Xml formats. In this doc we have the documentation about macros and program and E-records also. Statistician or project manager will submit this doc to FDA.

17. Can you use PROC COMPARE to validate listings? Why?

ANS: Yes, we can use PROC COMPARE to validate the listing because if there are many entries (pages) in the listings then it is not possible to check them manually. So in this condition we use PROC COMPARE to validate the listings.

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