Locating missing values is important in statistical data analysis. I've previously written about how to count the number of missing values for each variable in a data set. In Base SAS, I showed how to use the MEANS or FREQ procedures to count missing values. In the SAS/IML language, I
Today, SAS announces a new addition to its global certification program: you can now become "SAS Versions"-certified. Over the past 36 years, SAS has delivered hundreds of software products to the business analytics marketplace. Each of those products has a version number. As new revisions are released, the combination of
The title of this week's SAS author's tip amuses me. My non-programming mind is conjuring up a seriously cool PROC that leaps off the page. Or something like that. In reality, when looking for a potential tip in Wendy Bohnenkamp's and Jackie Iverson's book SAS Graphics for Java, I spotted many intriguing-looking graphs. Written for programmers
A 23-year Harvard and Columbia University study was recently published shedding new light on the long-term impacts of teachers with both high and low value-added estimates. Researchers Chetty, Friedman, and Rockoff tracked math and reading assessment data on over 2.5 million students from 1989-2009. They then incorporated 90% of these
Let's end 2012-Q1 with a graphic editorial comment: Forecast Accuracy vs. Effort Using a naïve model will achieve a certain level of forecast accuracy. That accuracy may be high if the demand is smooth and stable, or low if the demand is erratic. But you achieve this level of accuracy with virtually no
In a previous post I showed how to implement Stewart's (1980) algorithm for generating random orthogonal matrices in SAS/IML software. By using the algorithm, it is easy to generate a random matrix that contains a specified set of eigenvalues. If D = diag(λ1, ..., λp) is a diagonal matrix and
The March 28 edition of APICS extra features an article by Fred Tolbert on "The Seven Deadly Sins of Sales Forecasting." Although I have some objection to his Deadly Sin #1: Using Shipment History (and will discuss the objection in a forthcoming guest-post on the Institute of Business Forecasting blog),
The bookstore is a happening place at SAS Global Forum. You can shop onsite and save money on books, mingle with 30+ SAS authors, try to win giveaways (hint: follow @SASPublishing on Twitter and monitor the SAS Global Forum hashtag #SASGF12 and/or enter a couple of surveys) and chat with
Even Rod Serling recognized that sometimes we can't forecast worth a darn. "The Rip Van Winkle Caper" is an episode from Season 2 of the television series, The Twilight Zone, and first aired in 1961. It involves four train robbers who steal a million dollars worth of gold bars, hide
Because I am writing a new book about simulating data in SAS, I have been doing a lot of reading and research about how to simulate various quantities. Random integers? Check! Random univariate samples? Check! Random multivariate samples? Check! Recently I've been researching how to generate random matrices. I've blogged
With the publication of JSL Companion: Applications of the JMP Scripting Language, by Theresa Utlaut, Georgia Morgan, and Kevin Anderson, novice scripters now have a resource that helps them go beyond the basics of the JMP Scripting Language (JSL). Why JSL? The authors have the answers: 1. Easy to start
SAS Global Forum 2012 is right around the corner. If you will be in Orlando, too, be sure to say hello! If you have ideas for improving SAS/IML software or you would like to discuss my blog, please visit me during my hours at the SAS/IML booth in the Demo
The fundamental units in the SAS/IML language are matrices and vectors. Consequently, you might wonder about conditional expression such as if v>0 then.... What does this expression mean when v contains more than a single element? Evaluating vector expressions When you test a vector for some condition, expressions like v>0
Did that set off a trigger for you? It did for my SAS SQL 1: Essentials class, packed with SQL and SAS programmers alike. To clarify matters I pulled up some examples to help get the differences quickly. Set operators and Joins are similar in that they both combine multiple
This week's tip comes from Ron Cody - SAS author and expert extraordinaire. Ron's written several bestselling SAS Press books including his latest SAS Statistics by Example. If you haven't taken a look at Ron's extensive work, I'd invite you to visit his author page. You can read a free chapter from each of
Earlier this week I described a common programming pattern in the SAS macro language. The pattern sets up a loop for processing each distinct value of a classification variable. The program uses the PROC SQL SELECT INTO feature to populate SAS macro variables. The effect: you can roll your own
As public safety officials leaf through their favorite criminal justice periodical they are greeted with pages and pages of analytics advertisements. These ads are laden with promises of robust and scalable solutions, improved efficiencies and, yes, the promise of prediction. While reading the advertisements, the mental conversation may go something
After my post on detecting outliers in multivariate data in SAS by using the MCD method, Peter Flom commented "when there are a bunch of dimensions, every data point is an outlier" and remarked on the curse of dimensionality. What he meant is that most points in a high-dimensional cloud
I've heard many questions during my 6 years as Sales Manager for SAS Publishing. I’ve noticed that we frequently get similar questions from customers. I’ve compiled a few of these frequently asked questions below with answers. I hope this helps. Please let us know what information would help you navigate our books. Question: I am
I have previously spoken about using custom formats and from SAS Information Maps and how they can be used to categorize data differently for your end users. The problem for some is that this requires establishing the format on the SAS server, typically on lockdown by the SAS Administrator. Another
Hello! I hope you had a chance to read about e-Learning in last week’s blog. For those of you who want to see and try e-Learning, please come visit me at the e-Learning booth at SAS Global Forum in Orlando. In the weeks to come I will tell you more
Covariance, correlation, and distance matrices are a few examples of symmetric matrices that are frequently encountered in statistics. When you create a symmetric matrix, you only need to specify the lower triangular portion of the matrix. The VECH and SQRVECH functions, which were introduced in SAS/IML 9.3, are two functions
How to write a SAS macro program to repeat your SAS processing for each value of a BY grouping variable.
Art Carpenter’s newest book, Carpenter’s Guide to Innovative SAS Techniques, offers advanced SAS programmers an all-in-one programming reference that includes advanced topics not easily found outside the depths of SAS documentation or more advanced training classes. No matter how you approach the use of SAS software, the techniques provided in
The SAS/IML language supports both row vectors and column vectors. This is useful for performing linear algebra, but it can cause headaches when you are writing a SAS/IML module. I want my modules to be able to handle both row vectors and column vectors. I don't want the user to
When the data is classified by multiple class variables, you can certainly create graphs using BY variables. This results in separate graphs, one for each level of the BY variable crossings. Each graph is scaled by its own data subset, and comparisons across BY levels is harder. When comparisons need to be
When you are constantly taking the data tables and completing joins to begin working on your reports or analysis it might be time to consider creating permanent views. Then you can just add the view to the Enterprise Guide project rather than dealing with the joins in a Query Builder
A recent discussion on the SAS-L discussion forum concerned how to implement linear interpolation in SAS. Some people suggested using PROC EXPAND in SAS/ETS software, whereas others proposed a DATA step solution. For me, the SAS/IML language provides a natural programming environment to implement an interpolation scheme. It also provides
This week's SAS tip on writing LSMEANS statements comes from the big spring-green book A Step-by-Step Approach to Using SAS for Univariate and Multivariate Statistics, Second Edition. Striking in appearance, this comprehensive guide by professors Norm O'Rourke, Larry Hatcher, and Edward J. Stepanski is a great resource for students, researchers, and data analysts.
A well-formed WHERE statement or subsetting IF can narrow down the output of your SAS DATA step. The SAS log does a good job of telling you how many records were processed by the action. For example, let's look at this simple DATA step with my "poor man's random sample",
