Hello,
I am using proc surveyreg to compare the mean of different groups. But I do not quite sure what the adjusted p-value exactly mean in the output.
the code:
the output:
I wonder whether the adjusted p-value is due to Bonferroni adjustment? or Tukey-test?
Thank you!
Hello,
You ask for a multiple-comparison adjustment of LS-means differences by the ADJUST= option on the LSMEANS statement, so you get it. 🙄
As method, you specify TUKEY (ADJUST=TUKEY) so it's a Tukey adjustment for the p-value.
More info in the doc.
Cheers,
Koen
Hello,
There's no need to do a BON (Bonferroni) correction on top of the TUKEY correction.
To me a TUKEY correction is often a good choice (less conservative than Bonferroni).
But feel free to select the best correction method for your situation:
Here's the doc of the ADJUST= option (for multiple comparison p-value adjustment).
LSMEANS statement (across procedures):
If you do not know what to choose: choose ADJUST=BON.
Cheers,
Koen
Hello @knighsson ,
A small add-on to the comment made by @StatDave .
The adjustment method you choose does not influence in any way the significance level that you set for the hypothesis test (a comparison is also a hypothesis test). The alpha-level (for your hypothesis test) is the probability of making a type I error and is subjectively chosen by the user UPFRONT.
If you choose 0.05 as alpha, it stays that way after adjustment (with BON or TUKEY or ...) because the p-values are inflated. SAS should inflate the p-values instead of reducing the alpha because SAS does not know what the significance level / alpha is (because it's in the head of the user).
Good luck,
Koen
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