Thanks Ivan and Peter. I had been extolling the virtues of long format to my students, and mentioning some its shortcomings with paired data like paired t.test. I then went off script (bad idea) to explain a workaround and fell down the rabbit hole. Thebug report <https://bugs.r-project.org/show_bug.cgi?id=14359> 14359 on this issue was first started in 2010 (several years after I had started using R), and finally resulted in a code change only in April 2024 - all of those years I was blissfully unaware and had developed some bad habits with regard to brittle order assumptions ;-)
Even after rechecking ?t.test I was not certain that I was remembering the old behavior correctly, so it is good to know my memory is intact. The help is accurate, but the various pieces are a little dissociated. I think I learned I could trust the brittle ordering assumption (undocumented) by careful trial and error years ago. Anyway, thanks for another great R learning experience -- It has been fun to see how thoughtfully and carefully the behavior of R base code is discussed before a change is made. I wonder if 14 years of thinking/discussion is a record. Also, I appreciate the suggestion to use *split()* without having to completely ditch the use of the paired = TRUE argument, even if it still includes brittle order assumptions for pairs. I must say that the Pair(x,y) ~ 1 formula syntax is not that easy for me to wrap my head around. I'll keep watching if there are further changes coming in R-devel Rob On 11/5/2025 6:28 AM, Peter Dalgaard wrote: > Yes. Of course, Pair() requires the data to be in wide format. It's been a > while (although not so long ago as some of the other things I cannot > remember...) but I think the reason was that the ...y~g, paired=TRUE... > format was considered too brittle with respect to sort order and subsetting. > > -pd > > >> On 4 Nov 2025, at 18.40, Ivan Krylov via R-help<[email protected]> wrote: >> >> В Tue, 4 Nov 2025 11:22:57 -0600 >> Robert Baer via R-help<[email protected]> пишет: >> >>> Errorin t.test.formula(value ~ time, data = data_long, paired = >>> TRUE) : >>> cannot use 'paired' in formula method >> This was changed in R-4.4.0: >> https://bugs.r-project.org/show_bug.cgi?id=14359 >> >> The news item (see news(grepl('paired', Text))) recommends the use of >> Pair(x1, x2) ~ 1 instead of the 'paired' argument. A further fix is >> currently in R-devel (but not R-patched): without it, Pair(x1, x2) does >> not handle the 'subset' argument. >> >> -- >> Best regards, >> Ivan >> >> ______________________________________________ >> [email protected] mailing list -- To UNSUBSCRIBE and more, see >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guidehttps://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. -- --- Robert W. Baer, Ph.D. Professor of Physiology Kirksville College of Osteopathic Medicine A.T. Still Univerisity of Health Sciences 800 W. Jefferson St. Kirksville, MO 63501 [[alternative HTML version deleted]] ______________________________________________ [email protected] mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide https://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
