The DO Loop

Learn SAS

Learn about the latest tips, tutorials, upcoming events and certifications

Analytics | Learn SAS

Visualization of percentile definitions in SAS

Rick WicklinMay 22, 2017 1

In last week's article about the Flint water crisis, I computed the 90th percentile of a small data set. Although I didn't mention it, the value that I reported is different from the the 90th percentile that is reported in Significance magazine. That is not unusual. The data only had

English

Learn SAS | Programming Tips

Rick WicklinMay 15, 2017 28

INTCK and INTNX: Two essential functions for computing intervals between dates in SAS

Last week I showed a timeline of living US presidents. The number of living presidents is constant during the time interval between inaugurations and deaths of presidents. The data was taken from a Wikipedia table (shown below) that shows the number of years and days between events. This article shows

English

Learn SAS | Programming Tips

Rick WicklinMay 10, 2017 2

Simulate lognormal data in SAS

A SAS customer asked how to simulate data from a three-parameter lognormal distribution as specified in the PROC UNIVARIATE documentation. In particular, he wanted to incorporate a threshold parameter into the simulation. Simulating lognormal data is easy if you remember an important fact: if X is lognormally distributed, then Y=log(X)

English

Advanced Analytics | Learn SAS | Programming Tips

Rick WicklinApril 19, 2017 50

Regression with restricted cubic splines in SAS

Restricted cubic splines are a powerful technique for modeling nonlinear relationships by using linear regression models. I have attended multiple SAS Global Forum presentations that show how to use restricted cubic splines in SAS regression procedures. However, the presenters have all used the %RCSPLINE macro (Frank Harrell, 1988) to generate

English

Data Visualization | Learn SAS

Rick WicklinApril 17, 2017 8

Visualize the 68-95-99.7 rule in SAS

A reader commented on last week's article about constructing symmetric intervals. He wanted to know if I created it in SAS. Yes, the graph, which illustrates the so-called 68-95-99.7 rule for the normal distribution, was created by using several statements in the SGPLOT procedure in Base SAS The SERIES statement

English

Advanced Analytics | Learn SAS

Rick WicklinFebruary 13, 2017 27

An easy way to run thousands of regressions in SAS

A common question on SAS discussion forums is how to repeat an analysis multiple times. Most programmers know that the most efficient way to analyze one model across many subsets of the data (perhaps each country or each state) is to sort the data and use a BY statement to

English

Learn SAS | Programming Tips

Rick WicklinJanuary 9, 2017 14

ODS OUTPUT: Store any statistic created by any SAS procedure

In the beginning, SAS created procedures and output. The output was formless and void. Then SAS said, "Let there be ODS," and there was ODS. Customers saw that ODS was good, and SAS separated the computation from the display and management of output. The preceding paragraph oversimplifies the SAS Output

English

Learn SAS

Rick WicklinDecember 19, 2016 9

Solve linear programming problems in SAS

In some applications, you need to optimize a linear objective function of many variables, subject to linear constraints. Solving this problem is called linear programming or linear optimization. This article shows two ways to solve linear programming problems in SAS: You can use the OPTMODEL procedure in SAS/OR software or

English

Learn SAS

Rick WicklinAugust 8, 2016 6

Use SAS formats to bin numerical variables

SAS formats are flexible, dynamic, and have many uses. For example, you can use formats to count missing values and to change the order of a categorical variable in a table or plot. Did you know that you can also use SAS formats to recode a variable or to bin

English

Learn SAS

Rick WicklinJuly 25, 2016 3

Statistical model building and the SELECT procedures in SAS

Last week I read an interesting paper by Bob Rodriguez: "Statistical Model Building for Large, Complex Data: Five New Directions in SAS/STAT Software." In it, Rodriguez summarizes five modern techniques for building predictive models and highlights recent SAS/STAT procedures that implement those techniques. The paper discusses the following high-performance (HP)

English

Blogs

Blogs

Learn SAS