## How to determine the optimal factor of PLS model

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2 years AGO
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Just like I provided the Y explained variance of cross validation. The optimal factor is 8 that The Unscrambler gave. I want to know how to determine the optimal factor by calculation algorithm not by eyes.

Thank you very much.

Xudong

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## Thread Reply

## Please briefly explain why you feel this answer should be reported .

Report CancelNo algorithm can automatically find the correct rank (or underlying structures) for every

data set. Cross validation and test set validation have shown to be conservative methods in

this context. The Unscrambler® adds a small punishing constant to the validated residual

variance for each factor added to the model because the absolute minimum validated variance

may not be the optimal number in terms of how many factors to interpret as systematic

variation. A punishing constant of 1 percent relative to the residual variance after 0 factors,

i.e. after centering and scaling, is added for each factor to avoid being too optimistic. The

logic is (see attachment for clarity):

Aopt = 0

FOR factors 1:AMax

Difference = (ResidualVariance(a) + a*0.01*ResidualVariance(0)) -(ResidualVariance(a+1) + (a+1)*0.01*ResidualVariance(0))

IF Difference > 0

Aopt = Aopt + 1

ELSE

BREAK

END

END

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## Please briefly explain why you feel this answer should be reported .

Report CancelI have tested the Unscrambler method you have provided. However, the results were not match with the Unscrambler recommend. The Y residual variance for Brix, dry matter and Flesh color had been uploaded. Could you help me to test the results for how Unscrambler software to determine optimal factor?

Thanks

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## Please briefly explain why you feel this answer should be reported .

Report CancelHow Unscrambler software to calculate Y Total Residual Variance when factor is zero (Factor-0).

Thanks.

Xudong