This blog post is a "mashup" of a couple of my previous posts, combining the lessons to create something brand new that I hope you will find useful. First, let's review what we know: SAS Enterprise Guide supports a scriptable object model, which allows you to write scripts or programs
A common mistake in bad or misused software is choosing a forecasting model based solely on the model’s “fit to history” (often referred to as “best fit” or “pick best” functionality). The software provides (or the forecaster builds) several competing models which are then evaluated against recent history. The model
I was recently asked the following question: I am using bootstrap simulations to compute critical values for a statistical test. Suppose I have test statistic for which I want a p-value. How do I compute this? The answer to this question doesn't require knowing anything about bootstrap methods. An equivalent
When you analyze data, you will occasionally have to deal with categorical variables. The typical situation is that you want to repeat an analysis or computation for each level (category) of a categorical variable. For example, you might want to analyze males separately from females. Unlike most other SAS procedures,
Of course, forecasting the stock market is not perfectly analogous to forecasting demand for a product. The asking price for a stock is largely "anchored" by the price of its most recent trades. While market values may appear to randomly drift up and down, or in a general direction, we generally
In this second of three flash reports from last week's Analytics2011 conference, we hear about a favorite topic of mine -- the relationship between demand volatility and forecastability. Rob Miller of Avantor Performance Materials, on Forecastability and Demand Volatility The "comet chart," illustrating the relationship between demand volatility and forecast
We'll interrupt the series on Why Forecasts are Wrong, with a report from the inaugural Analytics 2011 conference, held last week in Orlando. A2011 drew over 1025 attendees (from 44 states and over 25 counties). The Analytics conference series features a wide range of topics (including forecasting, optimization, data mining, text
In SAS/IML 9.22 and beyond, you can call the R statistical programming language from within a SAS/IML program. The syntax is similar to the syntax for calling SAS from SAS/IML: You use a SUBMIT statement, but add the R option: SUBMIT / R. All statements in the program between the
This week's featured tip is from master SAS user Art Carpenter and his classic book Carpenter's Complete Guide to the SAS REPORT Procedure. In his review for the book, Rick Mitchell-senior systems analyst at Westat-said "I am green with envy for the newest generation of SAS programmers because I wish that I had had this book in
"I think that my data are exponentially distributed, but how can I check?" I get asked that question a lot. Well, not specifically that question. Sometimes the question is about the normal, lognormal, or gamma distribution. A related question is "Which distribution does my data have," which was recently discussed
Years ago and a seemingly far galaxy away, I wrote about how to modify 9.1.3 to start Enterprise Guide users in a different location for the File folder. By default, the user only can access their personal SAS Temporary File. Why change this? I would prefer to use a central
I was contacted by SAS Technical Support regarding a customer who was trying to use SAS/IML to compute quantiles of the folded normal distribution. I had heard of the distribution, but it is not built into SAS and I had never worked with it. Nevertheless, I set out to understand
For the past year, I’ve had the pleasure of serving on the communications team of the National Collaborative for Bio-Preparedness (NCB-P), of which SAS is a partner and the analytics provider. That experience was heavy on my mind as I recently watched the film Contagion. I may drop some minor
In SAS/IML 9.22 and beyond, you can call any SAS procedure, DATA step, or macro from within a SAS/IML program. The syntax is simple: place a SUBMIT statement prior to the SAS statements and place an ENDSUBMIT statement after the SAS statements. This enables you to call any SAS procedure
Super authors Susan Slaughter and Lora Delwiche and their bestselling Little SAS Book series have empowered the user community for years. This dynamic duo has uncannily anticipated what SAS users need to know. And they've produced thoughtful and accessible books with remarkable speed. One of their most recent books The Little SAS Book for Enterprise Guide 4.2 provides
Within the SAS documentation there must be thousands of unique words. But ten words occur more than any others within the SAS documentation corpus: SAS, data, statement, option, set, value, variable, PROC, model, table. This is according to one of our staff terminologists, Vicki Leary, who helps to keep our use of these words consistent and
This week brought big news of one of the most cruel and heartless tyrants of the 21st century. This man is known for narcissistic behavior, surrounding himself with a cadre of beautiful women, sleeping in a different place every night, picking new favorites each week, and bringing tears and untold suffering
When I learn a new statistical technique, one of first things I do is to understand the limitations of the technique. This blog post shares some thoughts on modeling finite mixture models with the FMM procedure. What is a reasonable task for FMM? When are you asking too much? I
Halloween is around the corner and children everywhere will wear masks throughout their neighborhoods for a night of trick-or-treating fun and, likely, too much candy. A masking has also occurred in education policy with the No Child Left Behind Act, sans the candy at the end of the night. That
Two weeks ago I had the pleasure of reading Tom Wallace's new book, Sales & Operations Planning: Beyond the Basics. This is not an introductory "how to" book -- Tom and Bob Stahl have already written those -- but instead covers nine major companies that have implemented (and extended!) S&OP
Normal, Poisson, exponential—these and other "named" distributions are used daily by statisticians for modeling and analysis. There are four operations that are used often when you work with statistical distributions. In SAS software, the operations are available by using the following four functions, which are essential for every statistical programmer
Functionality to upload files onto the SAS server (from 9.2 on) is available using stored processes and an html input type="file". I introduced this topic last year in my blog post using the SAS Stored Process Developer Guide sample. Of course, it is never as easy as the sample is
I received the following email: Dear Dr. Wicklin, Why doesn't SYMPUT work in IML? In the DATA step, I can say CALL SYMPUT("MyMacro", 5) but this doesn't work in IML! Frustrated Dear Frustrated, The SYMPUT subroutine does work in SAS/IML software! However, the second argument to SYMPUT must be a
I previously wrote about using SAS/IML for nonlinear optimization, and demonstrated optimization by maximizing a likelihood function. Many well-known optimization algorithms require derivative information during the optimization, including the conjugate gradient method (implemented in the NLPCG subroutine) and the Newton-Raphson method (implemented in the NLPNRA method). You should specify analytic
Picture this – a student grabs the Programming 1 textbook, scans it quickly seemingly searching for something specific, and shakes his head indicating an unsuccessful search. He plants himself smack dab in the front row, looks me squarely in the eye, raises one eyebrow quizzically and says, “Bad words?” I
A popular use of SAS/IML software is to optimize functions of several variables. One statistical application of optimization is estimating parameters that optimize the maximum likelihood function. This post gives a simple example for maximum likelihood estimation (MLE): fitting a parametric density estimate to data. Which density curve fits the
What is the best way to organize your SAS work in a SAS Enterprise Guide project? There are no project templates or enforced structure, really, but isn't there a best practice? I don't have a single prescription for the best project organization. I believe that it depends on the nature
To celebrate the first anniversary of Statistical Programming with SAS/IML Software, you can now download the SAS/IML tip sheets (also called "cheat sheets") that I created for the book. At conferences, SAS Press displays these tip sheets next to my book. They have been very popular. Download these SAS/IML cheat
I've noticed that a lot of people want to be able to draw bar charts with confidence intervals. This topic is a frequent posting on the SAS/GRAPH and ODS Graphics Discussion Forum and on the SAS-L mailing list. Consequently, this post describes how to add errors bars to a bar
With an increasing volume of curriculum to cover and no time to spare, teachers often hit the ground running with the full throttle rigor and relevance critical to teaching and learning. However, I argue that the first two R’s are futile if teachers don’t have meaningful relationships with their students.
