Bioequivalence and Bioavailability Forum

jag009 ★★★ NJ, 2013-05-16 00:57 (4772 d 06:05 ago) Posting: # 10586 Views: 4,376	Elementary question on HVD datasets [General Statistics] Post reply
	Hi experts! This is a really elementary question... If you want to compute the individual subject T/R Ratios from a 1 Test 2 x Reference (partial rep) study, which is the correct way IYHO? 1) Test/(Average of 2x Ref treatments) 2) Average of [(Test/Ref treatment Replicate 1) and (Test/Ref Treatment Replicate 2)] Yes obviously the ratios are different... Thanks John

Helmut
★★★

Vienna, Austria,
2013-05-16 03:32
(4772 d 03:30 ago)

@ jag009
Posting: # 10587
Views: 3,438

No. 1

Post reply

Hi John,

❝ If you want to compute the individual subject T/R Ratios from a 1 Test 2 x Reference (partial rep) study, which is the correct way IYHO?

❝

❝ 1) Test/(Average of 2x Ref treatments)

❝ 2) Average of [(Test/Ref treatment Replicate 1) and (Test/Ref Treatment Replicate 2)]

❝

❝ Yes obviously the ratios are different...

Yep. See FDA’s famous partial rep. code:

data scavbe;

  merge test ref1 ref2;

  by seq subj;

  ilat=latt-(0.5*(lat1r+lat2r));

  dlat=lat1r-lat2r;

run;

Hey, your #1 is close! Since we are in log-scale (ilat are the differences of logs):
\(T/R=e^{ilat}\)
Or if you prefer untransformed data – the ratio of T and the geometric (!) mean of Rs:
\(T/R=T/\sqrt{\bar{R}_1\times \bar{R}_2}\)

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jag009 ★★★ NJ, 2013-05-16 17:57 (4771 d 13:05 ago) @ Helmut Posting: # 10591 Views: 3,394	No. 1 Post reply
	Thanks Helmut

Elementary question on HVD datasets [General Sta­tis­tics]

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Elementary question on HVD datasets [General Statistics]