Understanding the DOE "generating rules"

[#1]

I've searched high and low but have found no useful information about how the "generating rules" are used when creating screening designs. Yes, I understand that changing which boxes are selected changes the design that will be generated, but I haven't a clue how a particular combination of checked boxes leads to a particular design. It's purely trial and error and I haven't found anything helpful in the documentation. An explanation would be much appreciated. Thanks!

[#2 · Accepted solution]

The default generating rules in the screening platform provide the minimum aberration design. As you've noted, changing the boxes changes the design, and changes the "defining relation" that determines which effects are aliased. The default minimum aberration tries to minimize aliasing of the lower-order effects as much as possible.

Some design of experiments textbooks and papers provide tables of design generators that lead to designs with certain properties. Minimum aberration is a good general rule of thumb, but there are certainly other possibilities, such as maximizing the number of clear effects. If you are looking to estimate particular effects, I would suggest trying the Custom Designer rather than the Screening Design platform.

While there's not much information in the documentation, if you do an online search for "Defining Relation" and "Design Generators" you should find sufficient information. I will put forward a suggestion to the documentation team to provide more details in a future version of the documentation.

Hope that helps!

[#3]

JMP documentation is available in two places: 1) in JMP under the HELP menu and 2) @at http://www.jmp.com/support/help/.  The web version at jmp.com has a dedicated search box for documentation and uses a search algorithm and list of items found that is very informative. Consider searching online and bookmarking that location.

[#4]

Thanks, but I already know this – I’ve been using JMP for 20 years and know how to use the program and online help facilities. My question was very specifically about “generating rules” and the fact that JMP documentation provides no useful information about these.