Outliers in Van Westendorp model

#1
Good evening,
Is it common practice to exclude outliers in the data before producing a Van Westendorp chart? If so, which technique would you advise - looking at the IQR, Grubbs test etc?
Many thanks in advance for any comments on this.
 

hlsmith

Less is more. Stay pure. Stay poor.
#2
An initial step would likely be to confirm the source of an outlier. Moreover, is it really an outlier for the process, meaning something erroneous happened or is it just too extreme for your taste?