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Registernew regression rule for lambda_z in Phoenix: no change in implementation [Software]
posted by SDavis 
– UK, 2025-11-11 15:24 (219 d 04:50 ago) – Posting: # 24488
Views: 4,590
(edited on 2025-11-11 15:36)
hi, I happen to have a 4.1 user manual on my bookshelf, yes a real book (2003)... and you can see from the attached pages the text is almost the same as in 8.7. My understanding is the only change made was with v6.0 of WinNonlin, first Phoenix version, was not to allow Cmax.
I think the issue maybe the text is slightly ambiguous and people read into it, "and then you stop", however it always went all the way back to Tmax, (and from 6.0+; Tmax+1) before selecting the value with the largest Adj-R-Sq. I think "If the adjusted R2 does not improve, but is within 0.0001 of the largest adjusted R2 value, the regression with the larger number of points is used." infers that but I've asked that we make it clearer in future iterations of the help that all points are assessed.
Long story short, it hasn't changed for 20+years,
Regards, Simon. Manager, Support, Certara.
![[image]](img/uploaded/image267.jpg)
![[image]](img/uploaded/image269.jpg)
![[image]](img/uploaded/image270.jpg)
I think the issue maybe the text is slightly ambiguous and people read into it, "and then you stop", however it always went all the way back to Tmax, (and from 6.0+; Tmax+1) before selecting the value with the largest Adj-R-Sq. I think "If the adjusted R2 does not improve, but is within 0.0001 of the largest adjusted R2 value, the regression with the larger number of points is used." infers that but I've asked that we make it clearer in future iterations of the help that all points are assessed.
Long story short, it hasn't changed for 20+years,
Regards, Simon. Manager, Support, Certara.
—
Simon
Senior Scientific Trainer, Certara™
[link=https://www.youtube.com/watch?v=xX-yCO5Rzag[/link]
https://www.certarauniversity.com/dashboard
https://support.certara.com/forums/
Simon
Senior Scientific Trainer, Certara™
[link=https://www.youtube.com/watch?v=xX-yCO5Rzag[/link]
https://www.certarauniversity.com/dashboard
https://support.certara.com/forums/
Complete thread:
- new regression rule for lambda_z in Phoenix: bug or new feature? Shuanghe 2025-11-10 15:55 [Software]
![[Mix]](https://static.bebac.at/img/mix.png "open in Mix view")
- new regression rule for lambda_z in Phoenix: bug or new feature? Helmut 2025-11-11 08:42
- new regression rule for lambda_z in Phoenix: no change in implementationSDavis 2025-11-11 14:24
- new regression rule for lambda_z in Phoenix: no change in implementation Shuanghe 2025-11-11 22:38
- Old User’s Guides Helmut 2025-11-11 23:20
- Misinterpretation Helmut 2025-11-12 12:16
- Misinterpretation Shuanghe 2025-11-12 21:24
- Misinterpretation Helmut 2025-11-15 09:38
- Misinterpretation billdenney 2026-02-27 14:20
- Clarification Helmut 2026-02-27 15:29
- Misinterpretation Shuanghe 2025-11-12 21:24
- Rewording appreciated Helmut 2025-11-12 10:30
- Reason for failing to calculate lambda and Kel in Phoenix jag009 2026-01-29 04:20
- Reason for failing to estimate λz Helmut 2026-01-29 11:04
- Reason for failing to calculate lambda and Kel in Phoenix jag009 2026-01-29 04:20
- new regression rule for lambda_z in Phoenix: no change in implementation Shuanghe 2025-11-11 22:38
Ing. Helmut Schütz