Can't implement replicate runs with JMP Pro 18

[#1]

Hi,

I am new to JMP Pro 18 and am finding that I can't seem to get repeated runs on my design of experiments. I am using I-optimal for RSM and am trying to add replicate runs of 3 or 2 but then when I create a table of the design of experiment I only get one column for the response and not three. Please can someone help me fix this?

Kind regards,

Jasim

[#2 · Accepted solution]

Hi @JasimKhan,

Welcome in the Community !
I think there is a confusion between repetition and replication :

• Repetition is about making multiple response(s) measurements on the same experimental run(s) (same sample(s) without any resetting between measurements). Repetitions only reduce the variation from the measurement system (by using the average of the repeated measurements). Repetitions can be added manually in a data table as new columns, as you're repeating the measurement on the same experimental unit. You can then use these columns to calculate and model the average measurement, variance, etc ...
• Replication is about making multiple independent randomized experimental runs (multiple samples with resetting between each runs) for each treatment combination. Replications reduce the total experimental variation (process + measurements) in order to provide an estimate for pure error and reduce the prediction error (with more accurate parameters estimates). They are added automatically (after design generation or augmentation) in a data table as new rows, as they are independent experimental runs.

In JMP, depending on the platform used, you can have Replicate Runs or Replicates :

• In a "Classical design", JMP displays "Number of Replicates", meaning here the number times to perform each run (in addition to the original runs),
• In a "Custom design" (like yours) JMP displays "Number of Replicate Runs", meaning here the number of run(s) to replicate.

You can also use the platform "Augment Design" to replicate a design.

Hope this answer will help you,

[#3]

Hi Victor_G,

Thank you very much for the clarification, I now understand the difference and have gone ahead used replicate runs instead and now it works! I am getting multiple rows for the same treatment condition. I am using an I-optimal RSM experimental design, I am guessing JMP decides on where to place the replicate runs but is there a way to decide for myself where these replicate runs are placed? Again, thank you for your explanation; it really helped!

Kind regards,

Jasim

[#4]

Hi @JasimKhan,

JMP choose the location of replicate runs based on your optimality criterion, in this case based on the maximum prediction variance in your experimental space, in order to reduce the average prediction variance (I-optimality criterion).
If you want to decide yourself, you can create a design without replicate runs, copy-paste the treatments (rows) you want to replicate, and then randomize the complete design.

All the best with your experimental topic,