Bioequivalence and Bioavailability Forum • randomization: runs test

randomization: runs test [Regulatives / Guidelines]

posted by Helmut – Vienna, Austria, 2012-06-16 16:42 (4749 d 21:58 ago) – Posting: # 8756
Views: 13,256

Hi ElMaestro!

❝ I don't think I would use a runs test prior to releasing a randomisation scheme. This screws the principle of randomness; even random sequences will have a significant runs test occasionally and still be 'random' whatever that words means.

OK, but see my A1 above.

❝ ElMaestro's approach: […]

Nice; especially your remarks about NLYWs. Concerning your #3:

require(tseries)

set.seed(16062012)

size      <- 24

sims      <- 1e6

nonrandom <- 0

for (i in 1:sims) {

  x <- 1

  while (sum(x) != 0) x <- sign(rnorm(size))

  x[x ==  1] <- "RT"

  x[x == -1] <- "TR"

  x   <- as.factor(x)

  rt  <- runs.test(x)

  sig <- rt$p.value

  if (sig < 0.05) nonrandom <- nonrandom + 1

}

cat(paste("‘nonrandom’ runs: ", format(100*nonrandom/sims, digits = 4), "%\n"))

Gave 5.895% on your matey’s machine. Don’t know whether 20+ years after the deficiency letter mentioned above inspectors would still react similarly.

—
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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: validation Helmut 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 testHelmut 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