Kenward-Roger? [Study Assessment]
Hi Angus,
Really? Still I can’t reproduce results of NCSS in R (data prepared like in this post).
Satterthwaite
Kenward-Roger
Modified results of NCSS from a previous posts:
As zizou suspected in this post there are differences in the SEs (therefore, we get different CIs even if DFs are identical) – which leaves the question open why they are different when compared to the other packages. NCCS seems to use Satterthwaite’s DFs and not Kenward-Roger’s (contrary to the documentation and what Jerry told you).
❝ Jerry from NCSS reports the following:
❝
❝ We have looked into this and resolved it in our own minds. NCSS uses the Kenwood-Rogers method for degrees of freedom which is an extension of the Satterthwaite method.
Really? Still I can’t reproduce results of NCSS in R (data prepared like in this post).
library(lmerTest)
library(pbkrtest)
muddle <- lmer(log(Cmax) ~ log(Dose) + (1|Subj), data=resp)
sum.Satt <- summary(muddle, ddf="Satterthwaite")
res.Satt <- data.frame(0:1, sum.Satt$coeff[ , "Estimate"],
sum.Satt$coeff[, 2],
sum.Satt$coeff[, 3],
sum.Satt$coeff[, 1]-
qt(1-0.05, sum.Satt$coeff[, 3])*
sum.Satt$coeff[, 2],
sum.Satt$coeff[, 1]+
qt(1-0.05, sum.Satt$coeff[, 3])*
sum.Satt$coeff[, 2],
row.names=NULL)
sum.KR <- summary(muddle, ddf="Kenward-Roger")
res.KR <- data.frame(0:1, sum.KR$coeff[ , "Estimate"],
sum.KR$coeff[, 2],
sum.KR$coeff[, 3],
sum.KR$coeff[, 1]-
qt(1-0.05, sum.KR$coeff[, 3])*
sum.KR$coeff[, 2],
sum.KR$coeff[, 1]+
qt(1-0.05, sum.KR$coeff[, 3])*
sum.KR$coeff[, 2],
row.names=NULL)
names(res.KR) <- names(res.Satt) <- c("B", "PE", "SE", "df",
"CLlower", "CLupper")
print(round(res.Satt, 4), row.names=FALSE)
print(round(res.KR, 4), row.names=FALSE)
Satterthwaite
B PE SE df CLlower CLupper
0 1.9414 0.2431 9.1956 1.4968 2.3860
1 0.7617 0.0473 5.8961 0.6696 0.8539
Kenward-Roger
B PE SE df CLlower CLupper
0 1.9414 0.2431 9.0915 1.4962 2.3866
1 0.7617 0.0473 5.7527 0.6692 0.8543
Modified results of NCSS from a previous posts:
B PE SE df CLlower CLupper
0 1.9414 0.2496 9.2 1.4849 2.3978
1 0.7617 0.0492 5.9 0.6659 0.8576
As zizou suspected in this post there are differences in the SEs (therefore, we get different CIs even if DFs are identical) – which leaves the question open why they are different when compared to the other packages. NCCS seems to use Satterthwaite’s DFs and not Kenward-Roger’s (contrary to the documentation and what Jerry told you).
—
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Science Quotes
Dif-tor heh smusma 🖖🏼 Довге життя Україна!
![[image]](https://static.bebac.at/pics/Blue_and_yellow_ribbon_UA.png)
Helmut Schütz
![[image]](https://static.bebac.at/img/CC by.png)
The quality of responses received is directly proportional to the quality of the question asked. 🚮
Science Quotes
Complete thread:
- Dose Proportionality and Variance AngusMcLean 2016-05-11 16:55 [Study Assessment]
- More information, please Helmut 2016-05-12 14:34
- More information, please AngusMcLean 2016-05-13 16:40
- Setup in Phoenix/WinNonlin Helmut 2016-05-14 02:26
- Setup in Phoenix/WinNonlin AngusMcLean 2016-05-14 18:54
- Setup in Phoenix/WinNonlin Helmut 2016-05-15 14:47
- Setup in Phoenix/WinNonlin AngusMcLean 2016-05-15 15:17
- Phoenix 64 Warning Helmut 2016-05-15 15:56
- Phoenix 64 Warning AngusMcLean 2016-05-15 20:11
- OT: imperial vs. metric units Helmut 2016-05-16 16:26
- Phoenix 64 Warning AngusMcLean 2016-05-15 20:11
- Setup in Phoenix/WinNonlin ElMaestro 2016-05-15 20:54
- Setup in Phoenix/WinNonlin AngusMcLean 2016-05-15 22:30
- Phoenix 64 Warning Helmut 2016-05-15 15:56
- Setup in Phoenix/WinNonlin AngusMcLean 2016-05-15 15:17
- Setup in Phoenix/WinNonlin Helmut 2016-05-15 14:47
- Setup in Phoenix/WinNonlin AngusMcLean 2016-05-16 21:00
- NCSS vs. PHX/WNL vs. SAS Helmut 2016-05-17 01:50
- NCSS vs. PHX/WNL vs. SAS - Validation? mittyri 2016-05-18 08:23
- Diagnostics ElMaestro 2016-05-18 09:20
- Diagnostics: R and Phoenix Helmut 2016-05-18 15:14
- Diagnostics: R zizou 2016-05-22 19:07
- Diagnostics: R Helmut 2016-05-23 01:22
- SASian potpourri d_labes 2016-05-24 12:02
- Compilation Helmut 2016-05-24 14:27
- REML or not d_labes 2016-05-24 16:33
- complete or not Helmut 2016-05-24 16:57
- Compilation AngusMcLean 2016-05-26 16:46
- doubts about NCSS Helmut 2016-05-26 19:13
- Doubts about NCSS zizou 2016-05-26 23:38
- doubts about NCSS Helmut 2016-05-26 19:13
- Compilation AngusMcLean 2016-05-28 00:51
- Kenward-Roger?Helmut 2016-05-28 15:59
- 90% confidence interval for R_dnm Shuanghe 2019-01-04 17:45
- 90% confidence interval for R_dnm d_labes 2019-01-05 14:01
- Visualizing lmer and limits mittyri 2019-01-06 17:00
- Visualizing lmer and limits Shuanghe 2019-01-07 11:05
- Visualizing lmer and limits d_labes 2019-01-07 15:08
- Visualizing lmer and limits mittyri 2019-01-13 23:53
- 90% confidence interval for R_dnm Shuanghe 2019-01-07 10:53
- 90% confidence interval for R_dnm d_labes 2019-01-07 15:17
- 90% confidence interval for R_dnm Shuanghe 2019-01-07 17:11
- 90% confidence interval for R_dnm d_labes 2019-01-07 18:24
- offtop: greek letters and tables mittyri 2019-01-08 00:19
- OT: greek letters and symbols Helmut 2019-02-02 16:04
- 90% confidence interval for R_dnm Shuanghe 2019-01-07 17:11
- 90% confidence interval for R_dnm d_labes 2019-01-07 15:17
- Visualizing lmer and limits mittyri 2019-01-06 17:00
- 90% confidence interval for R_dnm d_labes 2019-01-05 14:01
- REML or not d_labes 2016-05-24 16:33
- Compilation Helmut 2016-05-24 14:27
- SASian potpourri d_labes 2016-05-24 12:02
- Diagnostics: R Helmut 2016-05-23 01:22
- Diagnostics: R zizou 2016-05-22 19:07
- Diagnostics: R and Phoenix Helmut 2016-05-18 15:14
- Smith’s paper Helmut 2016-05-18 14:44
- Smith’s paper d_labes 2019-01-05 15:00
- Diagnostics ElMaestro 2016-05-18 09:20
- NCSS vs. PHX/WNL vs. SAS - Validation? mittyri 2016-05-18 08:23
- NCSS vs. PHX/WNL vs. SAS Helmut 2016-05-17 01:50
- Setup in Phoenix/WinNonlin AngusMcLean 2016-05-14 18:54
- Setup in Phoenix/WinNonlin Helmut 2016-05-14 02:26
- More information, please AngusMcLean 2016-05-13 16:40
- More information, please Helmut 2016-05-12 14:34