Bioequivalence and Bioavailability Forum

Non-informative “profiles” [General Sta­tis­tics]

posted by fno  – Belgium, 2014-03-12 12:18 (4136 d 22:52 ago) – Posting: # 12604
Views: 10,304

Hi ElMaestro,

❝ [...] Setting them to zero is not an optimal solution (My girlfriend hasn't spoken to me for three weeks. Which means she hasn't expressed any anger. Which means she probably isn't angry with me....) ❝

Setting them to missing is not an optimal solution either (My girlfriend hasn't spoken to me for three weeks... does not necessarily imply that I actually do not have a girlfriend ).

I completely agree that observing a flat BLQ profile is an important information to take into account in the planning of future studies... but in the meantime, you still have to complete the statistical reporting of the current study .
My gut feeling is that simply ignoring these BLQ values does introduce a quite important bias (e.g. systematic overestimation of the geometric mean).
Of course, any of the approaches I previously mentioned would also results into some bias, but hopefully less systematically and in a lower extent than simply discarding the BLQ values.

Complete thread:

• Log-transformation of "null" PK para­meters fno 2014-03-11 12:18 
  • Non-informative “profiles” Helmut 2014-03-11 13:29
    • Non-informative “profiles” Ohlbe 2014-03-11 13:47
      • Non-informative “profiles” Helmut 2014-03-11 14:04
        • Non-informative “profiles” fno 2014-03-11 15:52
          • Non-informative “profiles” Helmut 2014-03-11 17:22
            • Non-informative “profiles” ElMaestro 2014-03-11 18:50
              • OT: log(0) - NaN, NA or what d_labes 2014-03-12 08:59
                • OT: log(0) - NaN, NA, ‘.’, –∞, or empty Helmut 2014-03-12 15:31
              • Non-informative “profiles”fno 2014-03-12 11:18
                • Non-informative “profiles” nobody 2014-03-12 13:18