I recently posted an article about representing uncertainty in rankings on the blog of the ASA Section for Statistical Programmers and Analysts (SSPA). The posting discusses the importance of including confidence intervals or other indicators of uncertainty when you display rankings. Today's article complements the SSPA post by showing how
I recently blogged about how to eliminate a macro loop in favor of using SAS/IML language statements. The purpose of the program was to extract N 3x3 matrices from a big 3Nx3 matrix. The main portion of my PROC IML program looked something like this: proc iml; ... do i=0
SAS procedure SUMMARY is a quick method of converting your detail table to a fully summarized one. Included is a sample. The key option to set is the NWAY - this generates the lowest level of summary for use in the OLAP cube. Essentially - the class statement contains all
In the computer software industry, 35 years is like an eon. I mean, 35 years ago, the computing power that I carry around within my mobile phone didn't even exist all in one place; but if it did, it would have filled an entire building. That's why the recent posting
Statistical programmers can be creative and innovative. But when it comes to choosing names of variables, often x1, x2, x3,... works as well as any other choice. In this blog post, I have two tips that are related to constructing variable names of the form x1, x2,..., xn. Both tips
We're having an early spring in North Carolina. Trees are budding, flowers are blooming, and the warmer temperatures make even a pistol whipping more enjoyable. What better way to take advantage of the new season than filling your spring with educational opportunities in forecasting. Plan in Perfect Sync with Customer
Loony. Zany. Brilliant. Hysterical. Those are some of the adjectives I use to describe The Far Side® cartoons by Gary Larson from the 1980s and early '90s. I recently rediscovered an old book, The Far Side Gallery 2, which collects some of the best of Larson's wonderfully wacky cartoons. Every
SAS Global Forum 2011 just over two weeks away. The R&D and product management teams are preparing the demos to show on stage during the highly-visible opening sessions. A tremendous amount of work goes into planning the program. It's great to see what they come up with. When it comes
In a previous blog post, I showed how to use the SAS/IML SORT and SORTNDX subroutines to sort rows of a matrix according to the values of one or more columns. There is another common situation in which you might need to sort a matrix: you compute a statistic for
Sorting is a fundamental operation in statistical programming, and most SAS programmers are familiar with PROC SORT for sorting data sets. But did you know that you can also sort rows of a SAS/IML matrix according to the value of one or more columns? This post shows how. Sorting a
In my spare time, I enjoy browsing the StackOverflow discussion forum to see what questions people are asking about SAS, SAS/IML, and statistics. Last week, a statistics student asked for help with the following homework problem: I need to generate a one-dimensional random walk in which the step length and
Several times a year, I am contacted by a SAS account manager who tells me that a customer has asked whether it is possible to convert a MATLAB program to the SAS/IML language. Often the customer has an existing MATLAB program and wants to include the computation as part of
When I began my job at SAS in 1999 (I was only 14 years old at the time), one of my responsibilities was taking over the production of a listserv called NEWDOCNEWS. The listserv consisted of all the new titles from Books By Users (now SAS Press) and SAS Documentation
String comparisons in SAS software are case-sensitive. For example, the uppercase letter "F" and lowercase letter "f" are treated as unique characters. When these two letters represent the same condition (for example, a female patient), the strings need to be handled in a case-insensitive manner, and a SAS programmer might
Do you have many points in your scatter plots that overlap each other? If so, your graph exhibits overplotting. Overplotting occurs when many points have similar coordinates. For example, the following scatter plot (which is produced by using the ODS statistical graphics procedure, SGPLOT) displays 12,000 points, many of which
The ODS Graphics Designer allows you to design and build your own statistical graphs in SAS, without having to learn how to program in the new graph template language (GTL). The ODS Graphics Designer is a rich user interface that allows you to design these graphs based upon your own
I don't use the SAS macro language very often. Because the SAS/IML language has statements for looping and evaluating expressions, I rarely write a macro function as part of a SAS/IML programs. Oh, sure, I use the %LET statement to define global constants, but I seldom use the %DO and
If you haven't signed up for SAS Global Forum 2011 in Las Vegas, you'd better get moving: February 28 is the last day for early registration and the discounted hotel prices. You should also sign up for the pre-conference statistical tutorials, which are filling up fast! I was tempted to
As we discussed last week, the forecasting process is often contaminated by individuals whose input makes the forecast worse. Sometimes this is intentional. For example, if I'm tired of hearing customers complain about out-of-stocks on retail shelves, I'll try to drive up the forecast so that more inventory will be
I was inspired by Chris Hemedinger's blog posts about his daughter's science fair project. Explaining statistics to a pre-teenager can be a humbling experience. My 11-year-old son likes science. He recently set about trying to measure which of three projectile launchers is the most accurate. I think he wanted to
I’m sure you will all agree that a programmer’s favorite task is to maximize efficiency thus enhancing performance. Dear reader, in this blog post I’ll share my best programming practices so that you can benefit from what I typically show my students in class. At the end I’d like to
I don't know much about the SQL procedure, but I know that it is powerful. According to the SAS documentation for the SQL procedure, "PROC SQL can perform some of the operations that are provided by the DATA step and the PRINT, SORT, and SUMMARY procedures." Recently, a fellow blogger,
Contributed by Chris Hemedinger, coauthor of SAS for Dummies, Second Edition, the genius behind The SAS Dummy blog, and the moderator of the SAS Enterprise Guide discussion forum. The SAS log is your source for information if you want to know the following: What SAS did while running your program
If you are a statistical programmer, sooner or later you have to compute a confidence interval. In the SAS/IML language, some beginning programmers struggle with forming a confidence interval. I don't mean that they struggle with the statistics (they know how to compute the relevant quantities), I mean that they
A recurring theme of The Business Forecasting Deal (both this blog and the book) is that forecasting is a huge waste of management time. This doesn't mean that forecasting is pointless, irrelevant, or entirely useless in running our organizations. It only means that the amount of time, money, and human
The Flowing Data blog posted some data about how much TV actors get paid per episode. About a dozen folks have created various visualizations of the data (see the comments in the Flowing Data blog), several of them very glitzy and fancy. One variable in the data is a categorical
I've known several people who were raised during the Great Depression, and I've observed that they are very mindful of waste. My wife's grandmother used to save plastic bags, twist ties, and relatively clean aluminum foil for potential reuse in the household -- because such materials were once scarce. The
Suppose that you want to create a matrix in SAS/IML software that has a special structure, such as a tridiagonal matrix. How do you do it? Or suppose that you want to find elements of a matrix A such that A[i,j] satisfies a certain condition. How do you get the
Brian Whittington mentioned last month that government is innovating, and at great speed. Based on what I’ve seen in our line of work with state and local governments around the country in the past year, I have to agree. In the face of today’s daunting fiscal challenges, state and local
If you tell my wife that she's married to a statistical geek, she'll nod knowingly. She is used to hearing sweet words of affection such as You are more beautiful than Euler's identity. or My love for you is like the exponential function: increasing, unbounded, and transcendental. But those are
