martin
★★  

Austria,
2018-07-23 22:17
(2074 d 21:40 ago)

Posting: # 19086
Views: 3,215
 

 visualization of power-law model [General Sta­tis­tics]

Dear colleagues,

I would be happy to get the forum members thoughts regarding graphical display of the outcome of a dose-proportionality assessment based on the power-law model

In case that the power law model used to assess dose proportionality consists only of fixed factors intercept and slope I would think a figure like Figure 1 and 3 in the Smith et al paper (Smith et al. , 2000. Confidence interval criteria for assessment of dose proportionality. Pharm Res. 17:1278-1283) is good way to go.

However, frequently the corresponding model includes period and sequence effect as additional fixed effects (e.g. Williams design) and I am looking for some thoughts how to adequately visualize the corresponding results (other than showing the observed data and corresponding predictions grouped by sequence and period in a lattice plot or residual plots).

Best regards

Martin
d_labes
★★★

Berlin, Germany,
2018-07-26 16:49
(2072 d 03:08 ago)

@ martin
Posting: # 19105
Views: 2,581
 

 visualization of power-law model

Dear Martin,

❝ In case that the power law model used to assess dose proportionality consists only of fixed factors intercept and slope I would think a figure like Figure 1 and 3 in the Smith et al paper (Smith et al. , 2000. Confidence interval criteria for assessment of dose proportionality. Pharm Res. 17:1278-1283) is good way to go.


I think so.

❝ However, frequently the corresponding model includes period and sequence effect as additional fixed effects (e.g. Williams design) and I am looking for some thoughts how to adequately visualize the corresponding results (other than showing the observed data and corresponding predictions grouped by sequence and period in a lattice plot or residual plots).


For sake of simplicity I would go with the same plots as in the first case.
Only if period effects and/or sequence effects have a greater magnitude than the power law you will have a scatter in the data which seems not fit. I would expect such an behavior in only very rare cases, if any. If you have such a case, 'correct' your data for the period and/or sequence effects and plot then.

Hope you are well.

Regards,

Detlew
UA Flag
Activity
 Admin contact
22,957 posts in 4,819 threads, 1,636 registered users;
85 visitors (0 registered, 85 guests [including 11 identified bots]).
Forum time: 18:57 CET (Europe/Vienna)

Nothing shows a lack of mathematical education more
than an overly precise calculation.    Carl Friedrich Gauß

The Bioequivalence and Bioavailability Forum is hosted by
BEBAC Ing. Helmut Schütz
HTML5