Top 10 posts from The DO Loop in 2022


Last year, I wrote almost 90 articles for The DO Loop blog. My most popular articles were about SAS programming, data visualization, statistics and data analysis, and matrix computations. If you missed these articles when I published them—or if you want to read them again!— here is the "Reader's Choice Awards" for some of the most popular articles from 2022:

SAS programming

Random Four-Letter IDs

Data visualization

Missing Values in a Longitudinal Study

Statistics and data analysis

Data for Passing-Bablock Regression
  • Passing-Bablock regression: This article provides SAS IML modules that perform Passing-Bablock regression in SAS. This is a regression technique in which the measurements of two variables (X and Y) are both measured with errors, which means that the data do not satisfy the assumptions for ordinary least-squares regression.
  • The McNemar test: This article shows how to perform the McNemar test and the exact McNemar test in SAS. It discusses a variation in the test that you might see in other software. McNemar's test is used to assess whether the proportion of subjects who have some attribute (for example, pain) before a treatment is different from the proportion after the treatment.
  • Bartlett's sphericity test: This article shows how to perform Bartlett's test for correlation on multivariate data to determine whether it is possible to reduce the dimensionality of the data by using a principal component analysis or a common factor analysis.

Matrix Computations

The Derivative of a Determinant

Surprisingly, my most popular blog post from 2022 was an article about how to compute the derivative of the determinant of a matrix. I write about matrix computations regularly, but, for obvious reasons, these articles tend not to be as popular as articles about SAS programming and data visualization.

The determinant indicates whether a linear transformation expands or contracts volume. The derivative of the determinant indicates the rate of change in the determinant as a parameter is varied. I did not previously know how to compute the derivative of a determinant, so I was excited to write about a fairly simple algorithm that gives the derivative. The article demonstrates a rowwise method to compute the derivative of the determinant as the sum of auxiliary matrices and provides examples.


Many of us make New Year resolutions. My annual resolution is to learn something new every week. If you want to learn something new in the New Year, read (or re-read!) these 10 popular articles from 2022. If you like what you read, consider subscribing to The DO Loop blog.


About Author

Rick Wicklin

Distinguished Researcher in Computational Statistics

Rick Wicklin, PhD, is a distinguished researcher in computational statistics at SAS and is a principal developer of SAS/IML software. His areas of expertise include computational statistics, simulation, statistical graphics, and modern methods in statistical data analysis. Rick is author of the books Statistical Programming with SAS/IML Software and Simulating Data with SAS.

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