Interview Questions for SAS Aspirants with Answers

The need for SAS experts is still high since an increasing number of businesses are depending on data-driven decision-making. Data explosion, analytics breakthroughs, industrial expansion, and the significance of big data and data science are some of the contributing reasons for the demand. Healthcare, banking, retail, and government are among the industries where SAS professionals find jobs. Review your skills with our interview questions for SAS and get started with our SAS course syllabus if you are a beginner.

SAS Interview Questions and Answers for Freshers

Here are the basic SAS interview questions and answers. 

1. What is SAS?

SAS stands for Statistical Analysis System. It is a powerful and widely used software suite for advanced analytics, business intelligence, data management, and predictive analytics, healthcare, finance, retail, and government sectors.

2. What are the key features of SAS?

Some of the key features of SAS are:

• Data Management: It comprises data integration, transformation, and cleaning, an area in which SAS shines.
• Advanced Analytics: It provides a wide range of statistical and analytical capabilities, including time series analysis, regression, classification, and clustering.
• Business Intelligence: To extract insights from data, SAS offers tools for generating interactive dashboards, reports, and visualizations.
• Predictive Analytics: Businesses can create predictive models for forecasting, risk assessment, and customer churn prediction with the help of predictive analytics. 

3. What are the major components of the SAS system?

The major components of the SAS system are:

• SAS Base: The fundamental programming language, data management, and statistical processes that form the basis of the SAS system.
• SAS/STAT: A group of sophisticated statistical techniques for data analysis is known as SAS/STAT.
• SAS/GRAPH: A collection of tools for making different kinds of graphs and charts.
• SAS/Enterprise Guide: An easy-to-use interface that allows users to analyze data without knowing how to write code.
• SAS/ACCESS: Tools for integrating and retrieving data from several sources, including databases and spreadsheets, are called SAS/ACCESS. 

4. Describe the distinction between a PROC step and a DATA step.

DATA step: For creating and modifying data. It generates new datasets, reads data, and makes transformations.

PROC step: For reporting and data analysis. It creates reports and uses statistical processes. 

5. What is a SAS dataset?

The SAS software generates and processes an SAS dataset, which is a structured collection of data arranged as a table with rows (observations) and columns (variables). 

In addition to the data values, the dataset contains descriptive information about the data, such as variable names, types, lengths, and formats, which essentially functions as a self-documenting file within the SAS system.  

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6. What is the PDV (Program Data Vector)?

SAS software uses a logical region in memory called a PDV (Program Data Vector) during the data step process. 

• It serves as a working space to construct a data set one observation at a time by temporarily storing data for each processed observation. 
• This allows for variable manipulation and calculation prior to writing the data to an output dataset.
• During the DATA phase, SAS processes data one observation at a time in the PDV, a temporary memory storage region.

7. What are arrays in SAS?

Several variables with related properties can be stored and altered using arrays. They can be applied to increase code efficiency and streamline tedious procedures.

8. Explain the use of the INPUT statement in SAS.

Data from external files is read into the PDV using the INPUT statement. The variables to be read and their formats are specified.

• It specifies how the data should be interpreted and assigned to variables within your dataset based on its format and layout in the source file. 
• It tells you which variables to read and where to find their values within each data record, allowing you to structure your data according to different input styles like list input or column input depending on your data arrangement. 
• The “INPUT” statement in SAS is used to read raw data from an external file or directly from the program (in-stream data) into an SAS data set.

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9. What are the different types of missing values in SAS?

Two categories of missing values are identified by SAS:

• System missing value: It is shown with a period (.).
• User-defined missing value: Any character or set of characters is possible.

10. How do you handle missing values in SAS?

There are several methods to deal with missing values, including:

• Replacing with a specific value: use the IF-THEN/ELSE clause.
• Excluding observations with missing values: Using the MISSING option or the WHERE statement, observations with missing values are excluded.
• Imputing missing values: Regression imputation and mean imputation are two methods for imputing missing variables.

11. What is the use of the PROC SORT procedure?

Data can be sorted using PROC SORT in either ascending or descending order based on one or more factors.

• Before performing other operations on your data, you can arrange it according to certain criteria, such as alphabetically by name or numerically by date, using SAS’s PROC SORT procedure.
• This process essentially “sorts” the data by arranging the observations within a data set in a specific order, usually by the values of one or more designated variables.

12. What is the use of the PROC MEANS procedure?

Using SAS’s PROC MEANS procedure, you can quickly find descriptive statistics for variables in a dataset, such as mean, median, standard deviation, count, minimum, and maximum values. These variables are frequently grouped by different categories within the data using “class” variables, which essentially gives you a quick overview of how the data is distributed across different groups.  

13. What is the purpose of the PROC FREQ procedure?

Frequency tables are produced by SAS’s PROC FREQ procedure, which counts the occurrences of each distinct value in a categorical variable (or multiple variables in a cross-tabulation). 

It also provides descriptive statistics like percentages and cumulative frequencies and can run statistical tests like chi-square tests to examine the relationships between variables in the data set.

14. What is the purpose of the PROC REG procedure?

The PROC REG procedure in SAS software allows you to perform linear regression analysis and fit a linear model to data by identifying the relationship between a dependent variable and one or more independent variables. 

• It is used to find the “best fit” line that explains how the dependent variable changes as the independent variables change, and more. 
• Additionally, it calculates regression coefficients and offers a range of diagnostic statistics to assess the model’s validity.  

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15. What is the purpose of the PROC SQL procedure?

You can run SQL queries on SAS datasets using PROC SQL. It offers a strong and adaptable method for data manipulation and analysis.

• The PROC SQL procedure in SAS gives users a way to carry out data operations like selecting, filtering, joining, and summarizing data using well-known SQL syntax within the SAS environment. 
• It enables users to manipulate and retrieve data from tables and views within an SAS dataset using Structured Query Language (SQL). 

16. What is the difference between the WHERE statement and the IF-THEN/ELSE statement?

WHERE statement: Before being read into the PDV, observations can be chosen based on a condition using the WHERE statement.

IF-THEN/ELSE statement: The PDV’s IF-THEN/ELSE statement is used to add new variables or change ones that already exist.

17. What is the purpose of the RETAIN statement in SAS?

You can carry a value across multiple observations for calculations that need data from previous rows by using the RETAIN statement in SAS to tell the system to “hold” or keep the value of a variable from one iteration of the DATA step to the next. 

This keeps the variable from being automatically reset to missing at the start of each new observation.  

18. What is the purpose of the BY statement?

In programming languages such as SAS, the “BY” statement tells the system to process data observations in groups, each of which is defined by a particular value of a designated “BY variable.” 

• It allows independent analysis or output generation for each unique group in the data set.
• It makes it possible to group and analyze the data according to a particular criterion.  

19. What is the purpose of the CALL SYMPUTX function?

Unlike the standard “CALL SYMPUT” function, which defaults to the most local symbol table available, the “CALL SYMPUTX” function in SAS gives you more control over where the macro variable is accessible within your SAS program by enabling you to explicitly specify which symbol table (local or global) to store the macro variable in.  

20. What are macro variables in SAS?

By essentially creating placeholder values that can be changed on the fly depending on the situation, a “macro variable” in SAS is a string variable that stores text that can be dynamically substituted into an SAS program. 

In other words, it’s a way to store and reference text snippets within your SAS code to modify it dynamically.  

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Advanced Interview Questions for SAS Programmer

Below are the advanced SAS interview questions and answers:

1. What are some common SAS functions?

Typical SAS functions include the following:

• AVG: Divides by the number of rows after adding the values of each row in a column. Missing and null values are ignored.
• TODAY: Provides an SAS date value representing the current day. The number of days since January 1, 1960, is represented by this figure.
• Proc Sort: A data set is sorted using Proc Sort.
• Proc Transpose: Turns a data set’s rows into columns.
• Proc Freq: Determines a variable’s frequency count and percentage.
• DEVIANCE: Using a probability distribution, returns the deviation.
• Date function: Uses the date, hour, minute, and second data to return an SAS datetime value.

Numerical, time, truncation, and character functions are some additional frequently used SAS functions.

2. What is the purpose of the LOG window in SAS?

Essentially functioning as a comprehensive record of everything that transpired during an SAS session, the LOG window in SAS is an essential tool for monitoring the execution of your SAS programs. 

It shows messages about the program’s status, including any errors, warnings, or notes that occurred during processing, enabling you to identify and troubleshoot issues within your code.  

Important things in the LOG window:

• Error Detection: This is where SAS warns you of serious issues that are preventing your application from operating correctly by displaying error warnings in red.
• Warning Messages: Warnings, which are typically shown in green, point to possible problems that need to be addressed but might not prevent the program from running.
• Informative Messages: The LOG pane displays informational notes in blue that verify successful code execution in addition to failures and warnings.
• Code Review: Every line of code that was run is visible, as is the execution time.
• Essential for troubleshooting: After executing an SAS program, always look at the LOG window to make sure everything went according to plan and spot any possible issues.

3. What is the purpose of the RESULTS window in SAS?

By displaying a list of all output objects produced during an SAS session, the “Results” window in SAS functions as a table of contents. 

By clicking on the appropriate entry within the window, users can quickly navigate through and access various sections of their analysis results, such as tables, graphs, and reports. In essence, it offers an organized summary of the output that was produced.  

Important details about the Results window:

• Output Display: Data sets, reports, graphs, and other output items produced by an SAS application are all listed in a hierarchical tree structure on the output display.
• Navigation: By selecting the appropriate entry in the Results box, you can rapidly go to particular output parts.
• HTML View: The “Results Viewer” window, which is connected to the Results window, shows the default output in HTML format.
• Management: By removing or renaming entries in the Results box, users can control output.

4. What is the purpose of the SASHELP library?

In addition to offering users easy access to sample data for testing code, learning new procedures, and exploring various SAS functionalities, the SASHELP library in SAS software acts as a repository for pre-loaded sample datasets and system information. 

Through its data views, SAS software also gives users access to behind-the-scenes information about the current SAS session.  

Key Features of SASHELP:

• Sample Data: Offers a vast array of varied sample datasets for users to use for demonstration and practice.
• System Information: Contains details on variables, formats, and other system parameters related to the current SAS session. These details are accessible through certain “views” in the library.
• Learning Tool: To learn how to do different statistical analyses and data manipulations, novice SAS users can make use of the easily accessible datasets.
• Testing Ground: Before implementing new code or processes on actual data, developers can test them on the sample data.  

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5. What is the purpose of the SASUSER library?

Users can customize their SAS environment by storing their preferences in a dedicated library that loads automatically when they launch a new session. 

The SASUSER library in SAS software is used to store a user’s personal customizations for their SAS session, including settings like window size, colors, fonts, and function key configurations.  

Key Points of SASUSER:

• Personalization: It stores the “profile catalog” of a user, which includes configuration options for personalizing their SAS interface.
• Automatic loading: SAS loads your saved preferences by automatically referencing the SASUSER library when you launch SAS.
• No need for a manual assignment: SAS automatically assigns a libref to the SASUSER library, so you don’t need to use a LIBNAME line to access it.
• Customization options: The SASUSER library allows you to store a variety of settings, including printer entries, function key definitions, window properties, and more.  

6. What is the purpose of the WORK library?

Essentially serving as a scratchpad for transient data manipulation, the SAS software’s “WORK” library is a temporary storage area that is automatically established at the beginning of each session and intended to retain data sets and files utilized during the current session. These files are subsequently erased at the end of the session.  

Important details regarding the WORK library:

• Temporary storage: This method removes the need to worry about permanently storing huge intermediate datasets by storing only the data required for the current SAS session. 
• Automatic creation: When you launch an SAS session, the WORK library is defined automatically. 
• One-level naming: The “WORK” libref is automatically assigned when referencing data in the WORK library, so you simply need to provide the dataset name without a library prefix. 
• Deletion at session end: When the SAS session concludes as planned, all of the data kept in the WORK library is erased. 

7. What is the purpose of the OPTIONS statement?

In programming languages like SAS, the “OPTIONS” statement is used to set or change the values of different system options. This allows you to customize the program’s settings for a particular task or environment by defining specific parameters like output formatting, data handling, or execution behavior depending on the context.  

Crucial elements of the OPTIONS statement:

• Customization: By defining distinct option names and their associated values inside the statement, you can modify a number of program behavior features.
• Global Impact: Unless they are overridden later in the code, changes made using the OPTIONS statement usually impact the entire program execution.
• Examples: 
  • Configuring the date format (for example, “DATESTYLE=DMY”).
  • Limiting the amount of output detail.
  • Outlining particular possibilities for processing data in specific ways.

8. What is the purpose of the TITLE statement?

Essentially serving as a heading that makes it obvious what the document or data being presented is about, a “TITLE statement” lets users give their reports or data sets a descriptive title for simple identification. It is used to specify the title that will appear at the top of a page or output.  

Essential elements of TITLE statements:

• Function: The text that will appear as a title on output, such as reports, listings, or printed data, is defined by this function.
• Application: Often utilized in data analysis tools and programming languages such as SAS and COBOL.
• Benefits:
  • Clearly defining a document’s or data set’s content enhances reading.
  • Facilitates the organization and navigation of vast volumes of information.  

9. What is the purpose of the FOOTNOTE statement?

The “FOOTNOTE” statement, which is typically found at the bottom of the page as a brief note denoted by a superscript number or symbol within the main text itself, is used in writing to provide extra information or to cite the source of a specific fact or piece of information mentioned in the text. In essence, it allows the reader to access additional details without interfering with the writing’s flow.  

Important details regarding footnotes:

• Provides context: Footnotes can provide further context or clarification for a particular textual point.
• Source citation: Mostly used to acknowledge the material’s original source, such as a book, paper, or research study, so that readers can confirm the facts.
• Academic writing: To support assertions made in the text, footnotes are frequently employed in academic writing.

10. What is the purpose of the LABEL statement?

In programming languages, a “LABEL” statement is a means to explicitly mark a statement for control flow purposes. It gives a line of code a descriptive name or identifier, which enables you to refer to that line later in the program using a “goto” statement, effectively jumping to that labeled section of code.  

Salient features of the LABEL statement:

• Identifying a line: A particular line of code is uniquely identified by its label.
• Used with “goto”: Typically, labels are used in conjunction with a “goto” statement, which points the program’s execution to the line that has the label attached to it.
• Cautionary use: The frequent use of “goto” statements is generally discouraged in modern programming methods since it can make code difficult to read and maintain, even if they can be helpful in some circumstances. 

Example:

data mydata;

  set sashelp.class;

  label Age = “Student’s Age in Years” 

        Grade = “Academic Grade Level”;

run; 

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11. What is the purpose of the FORMAT statement in SAS?

By defining the number of decimal places, date formats, and other presentation options based on the format used, you can essentially change how the data is presented without changing the actual data values stored in the dataset. The “FORMAT” statement in SAS is used to permanently associate a specific format with one or more variables, which controls how the values of those variables are displayed.  

12. What is the purpose of the INPUT statement with the @ symbol?

You have complete control over the data extraction process from a raw data file in SAS due to the “@” symbol in an INPUT statement, which functions as a pointer and lets you specify the precise column position within a data record where you want to start reading a variable value. You can read data fields in any order, even going backwards and forwards within the record.  

13. What is the purpose of the @@ symbol in the INPUT statement in SAS?

To read data from the same record more than once within a single data step loop, SAS uses the “@@” symbol at the end of an INPUT statement as a “line-hold specifier,” instructing SAS to keep the current input record in the buffer over several DATA step iterations.  

14. What is the purpose of the LENGTH statement in SAS?

The “LENGTH” statement in SAS defines the maximum length in bytes that should be used to store the values of variables in a data set. This effectively controls the amount of storage space allotted for each variable and is especially crucial when working with character variables.  

15. What is the purpose of the DROP statement in SAS?

By stating the variables you wish to drop, the “DROP” line in SAS lets you choose which variables to maintain and which to remove from the output data set. In other words, it removes specific data columns from the final dataset you are constructing within a DATA phase.  

DATA new_data;

  SET old_data;

  DROP age gender;  /* This will create a new data set “new_data” that excludes the “age” and “gender” variables from the original “old_data” data set. */

RUN;

16. What is the purpose of the KEEP statement in SAS and how does it work?

In SAS, the variables to be included in the output data set are specified by the KEEP statement. It is employed to restrict the output dataset’s variable count.

• In a DATA phase, the KEEP statement can show up anywhere.
• All output data sets produced in the same DATA phase are covered by the KEEP statement.
• The variables’ values are unaffected by the KEEP statement.
• Limiting the amount of variables is more effective when done with the KEEP statement.  

17. What is the purpose of the RENAME statement in SAS?

You can alter the variable names that will be sent to the output data set by using SAS’s “RENAME” statement to change the names of one or more variables inside a data set. 

This is effectively changing the names of existing variables to new ones while processing data in a data step.  

18. What is the purpose of the MERGE statement in SAS?

By combining observations from two or more datasets into a single new dataset, SAS’s MERGE statement essentially enables you to “join” data from many sources using shared variables, producing a single data set that incorporates pertinent information from each source.  

19. What is the purpose of the SET statement in SAS

In SAS programming, you can access data from existing datasets to create a new dataset within the data step by using the “SET” line to read observations from one or more existing SAS datasets and bring them into the current data step for additional processing and manipulation.  

Example:

DATA new_data;

  SET old_data1 old_data2;

  /* Perform calculations or manipulations on the data here */

RUN;

20. What are some common SAS programming errors?

Some of the typical SAS errors:

• Syntax errors:
  • Statements without semicolons at the end.
  • SAS keywords or variable names that are misspelled.
  • Unmatched quotation marks.
  • The location of the parenthesis is incorrect.
• Data type errors:
  • Trying to use non-numeric variables for arithmetic operations.
  • Not properly converting a character variable to a numeric variable.
• File handling errors:
  • Giving the path to a data file that doesn’t exist.
  • Inaccurate names or labels for data sets.
• Logic errors: 
  • Inaccurate conditional statements (such as those that use “>” rather than “<“).
  • Inaccurate variable assignment or other data manipulation logic within a data step.
• Function usage errors:
  • Utilizing a function with an incorrect number of parameters.
  • Misinterpreting a function’s output.
• Data sorting and merging errors:
  • Syntax errors in merge statements that result in unexpected data pairings.
  • Unexpected data order due to improper sorting criteria.

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Conclusion

These 40 SAS interview questions and answers cover a wide range of fundamental concepts and procedures within the SAS system. By understanding these topics, you can demonstrate a solid foundation in SAS programming and data analysis techniques. Gain expertise in data science concepts with our SAS training in Chennai.