Bioequivalence and Bioavailability Forum • randomization: validation

randomization: validation [Regulatives / Guidelines]

posted by Helmut – Vienna, Austria, 2012-06-15 19:39 (4750 d 11:36 ago) – Posting: # 8745
Views: 13,860

Dear Ravi!

I don’t think that you have to submit the code, but like all software it should be validated. I did it once for my own randomization in HP-UX Pascal based on the Wald–Wolfowitz runs test.
For SAS see here; set-up in other software is easy as well. For [image]

have a look at package tseries runs.test().

A simple randomization for a 2×2 cross-over with balanced sequences and random frequency of runs:

library(tseries)

#set.seed(15062012)              # uncomment this line for testing

size <- 24

sig  <- 0                        # break condition

while (sig < 0.05) {             # … until nonsignificant runs

  x <- 1                         # break condition

  while (sum(x) != 0) {          # … until balanced

    x <- sign(rnorm(size))       # random: -1 or +1

  }

  runs <- length(rle(x)$lengths) # No. of runs

  x[x==1]  <- "RT"               # nicer ‘looks’

  x[x==-1] <- "TR"

  x   <- as.factor(x)

  rt  <- runs.test(x)            # perform test

  sig <- rt$p.value              # p-value

  }

x                                # display randomization

rt                               # show test results

Should give (with the testing seed):

 [1] RT RT RT TR TR TR TR RT RT TR TR TR RT RT TR TR RT TR TR RT RT RT TR RT

Levels: RT TR



        Runs Test



data:  x 

Standard Normal = -0.8348, p-value = 0.4038

alternative hypothesis: two.sided

—
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Helmut Schütz

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Complete thread:

USFDA requirement for randomization Ravi 2012-06-15 13:39 [Regulatives / Guidelines]
- randomization: validationHelmut 2012-06-15 17:39
  - randomization: runs test? validation? d_labes 2012-06-16 13:10
    - randomization: runs test? validation? Helmut 2012-06-16 14:00
      - probability nearly zero? d_labes 2012-06-16 16:11
        
        probability nearly zero! Helmut 2012-06-16 17:08
        
        R-package randomizeBE d_labes 2012-07-06 09:54
        
        R-package randomizeBE Helmut 2012-07-06 12:51
  - randomization: validation ElMaestro 2012-06-16 13:31
    - randomization: runs test Helmut 2012-06-16 14:42
      - randomization: runs test ElMaestro 2012-06-16 14:48
        
        randomization: runs test Helmut 2012-06-16 15:10
      - very cool coding style ElMaestro 2012-06-16 19:12
        
        Better a good steal than a bad reinvention Helmut 2012-06-17 13:22
        
        Better a good steal than a bad reinvention ElMaestro 2012-06-17 19:58
        
        Sorry! Helmut 2012-06-18 13:26
        
        Sorry! ElMaestro 2012-06-18 15:19
        
        Dancing with the dice d_labes 2012-06-18 15:38
        
        Silly's randomization 2x2 xover d_labes 2012-06-18 16:30
        
        Silly's randomization 2x2 xover Helmut 2012-06-18 17:14
        
        Clumsy code Helmut 2012-06-18 17:42
        
        Clumsy code ElMaestro 2012-06-18 18:01
        
        Speed kills Helmut 2012-06-18 18:56
        
        Speed kills jag009 2012-09-17 21:46