I began 2016 by compiling a list of popular articles from my blog in 2015. This "People's Choice" list contains many interesting articles, but some of my personal favorites did not make the list. Today I present the "Editor's Choice" list of articles that deserve a second look.

I've grouped the articles into four broad topics: SAS programming, computational statistics, statistical graphics, and matrix computations.

### SAS programming

These two articles use Base SAS to accomplish some useful tasks:

- Many SAS procedures drop observations that contain a missing value for some variable. The remaining observations are called
*complete cases*. If you are writing your own analysis, you need to know how to obtain complete cases in SAS. - There are several ways to turn off ODS output in SAS. Learn five reasons you should use the ODS EXCLUDE statement to suppress SAS output.

### Computational statistics

For most analyses, you can call a built-in SAS procedure. However, I enjoy showing how to extend, modify, or explain a standard analyses by writing additional programming statements.

- Have you ever run a statistical procedure that does not converge to a solution? Learn about why some numerical optimization technique (such as Newton's method) diverge far from their initial states.
- Do you want to visualize the result of a multivariate regression? The regression coefficient plot displays the parameter estimates for a regression analysis.
- Do you use generalized linear models? Have you ever thought about the differences between a log-link model and a traditional OLS model? Read about how to visually compare two regression models that have different assumptions.
- Monte Carlo simulation is an important tool in the toolbox of the modern computational statistician. Learn how to perform Monte Carlo simulation in SAS for the analysis of contingency tables.

### Statistical graphics

Although many SAS procedure automatically produce appropriate statistical graphics, it is sometimes necessary to use the SGPLOT or the Graph Template Language (GTL) to create your own graphics.

- Did you know that you can create a heat map by using PROC SGPLOT in SAS 9.4m3?
- For some data and some analyses, it is important to know how to preserve the aspect ratio of the data in a graph.
- For continuous data, it can be convenient to associate an ordinal scale such as "low-medium-high." Learn how to overlay a discrete color ramp on a histogram of a continuous variable.

### Matrix computations

From the many articles that I wrote about matrix computations, the following list presents three topics that SAS programmers often ask about on discussion forums:

- How to create an array of matrices in SAS.
- Does it make sense to perform matrix multiplication with missing values? If so, how do you multiply with missing values in SAS?
- The rank of a matrix is the number of linearly independent columns. What is the best way to compute the rank of a matrix in SAS?

There you have it, 12 topics that I think are worth a second look. Did I omit your favorite article from *The DO Loop* in 2015? Leave a comment.