topic Re: 8-run Plackett-Burman with JMP14 in Discussions

8-run Plackett-Burman with JMP14

FabioRoselet — Fri, 15 Jun 2018 19:15:20 GMT

Hi everyone,

How can I perfrom an 8-run Plackett-Burman design with JMP14? Browsing the online documentation about Plackett-Burman suggests to include 4 additional runs and construct a 12-run Plackett-Burman design instead. However, a 12-run is just too much as I only have 4 factors... so a PB-8 would be enough for me.

Unfortunately, after choosing Classical > Screening Design and setting the responses (1) and factors (4) the list of designs do not offer a PB-8 option, only fractional factorials with some 2-factors interactions.

Is it possible to construct a PB-8 with JMP14?

Thanks!

Re: 8-run Plackett-Burman with JMP14

msharp — Fri, 15 Jun 2018 19:43:52 GMT

It doesn't look like JMP likes Plackett-Burman for 1 response 4 factors. The default example in their documentation is a 1 resposne 5 factors and this works as expected in both JMP 13/14. Removing one of the factors removes PB designs from the options in both JMP versions. Whether or not this is intended would be a question for JMP.

https://www.jmp.com/support/help/14/plackett-burman-design.shtml

Re: 8-run Plackett-Burman with JMP14

Mark_Bailey — Fri, 15 Jun 2018 19:59:23 GMT

I believe that the Plackett-Burman fractional factorial design is not shown because the regular fractional factorial in 8 runs (1) is the same, (2) has equivalent resolution, or (3) has better resolution.

Re: 8-run Plackett-Burman with JMP14

Mark_Bailey — Fri, 15 Jun 2018 20:07:40 GMT

Four factors does not seem like a screening experiment to me. It is a situation in which the screening principles are not likely to apply.

Eight runs does not have much power unless the effects are many times the standard deviation of the response.

You can't afford twelve runs and accept eight runs, so it seems that you know that main effects, for which regular and irregular fractional factorial designs are intended, are sufficient to model the response.

Why not use custom design?