SAS/R code of MSD method for comparing dis­so­lution [Dissolution / BCS / IVIVC]

posted by wligtenberg – The Netherlands, 2016-12-22 12:20 (2675 d 13:57 ago) – Posting: # 16874
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❝ DDSolver's source is locked, so I thought that, unless authors let you, no one can have a peek as how it works exactly. I have no idea how you figure this out but :thumb up: from me.


I didn't know that they tried to limit people to look at the code.
I just opened it in Libre Office (under linux) and I could see the code, nothing fancy.

❝ If they obtain low and upper limits as you said then I don't think it's correct. I'm not a statistician so my thinking might be naïve. For me, here the Mahalanobis distance is a measure of the difference in terms of "distance" and when there is no difference the distance would be zero; if there are difference, the distance would always be a positive number. Negative distance? :confused: Couldn't comprehend.


I agree that the distance should never be negative, and that if your CR somehow goes below zero, it should be truncated to zero.
However, the interesting thing is that for the rest of the data sets that I tried, that calculation comes up with the same values as your calculation.

Also it seems that the CR is always symmetrical around the Mahalanobis distance.
The DDsolver result fits in that observation, the results of the calculation with the R code does not in this case.

So even though the negative value of the lower bound might be incorrect, and should then be 0, for the rest it seems to work well.

:confused:

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