What is a good Q2 value?

What is a good Q2 value?

Q2 is the R2 when the PLS built on a training set is applied to a test set. So a good value for Q2 is a value that is close to the R2. That means that your PLS model works independently of the specific data that was used to train the PLS model. Adding more variables always makes R2 go up, but might not make Q2 go up.

What is q squared in PLS?

Q-squared (Q‍2) is the R-squared value that you get from applying the QSAR model to the test set instead of the training set. Since the model is not directly calibrated to fit the test set, Q-squared may or may not increase as you add more PLS factors.

What is F Square in SmartPLS?

f-square is effect size (>=0.02 is small; >= 0.15 is medium;>= 0.35 is large). f-square measured variance explain each exogenous variables in the models. Q-square is predictive validity, measured your model have predictive validity or nor (> 0 is good). Best regards, ghozali PLS Expert User.

When to use Q2 instead of R2 in PLS?

Q2 is the R2 when the PLS built on a training set is applied to a test set. So a good value for Q2 is a value that is close to the R2. That means that your PLS model works independently of the specific data that was used to train the PLS model.

What are the metrics used in PLS regression?

From documentation and other readings regarding PLS regression I’ve come to understand that there are generally two metrics used to evaluate the performance of the algorithm. R 2 is calculated as 1 – residual sum of squares (RSS) and the total sum of squares (TSS):

What’s the significance of a PLS / OPLS model?

Concerning the Q2 parameter, a significance threshold of 0.5 is generally admitted. However, during the last few years, many PLS-DA/OPLS-DA models built using SIMCA have been published with Q2 values lower than 0.5.

When to increase R-Squared and Q-Squared?

Since the model is not directly calibrated to fit the test set, Q-squared may or may not increase as you add more PLS factors. But if it’s a good model (i.e., it embodies the SAR and you’ve picked a reasonable number of PLS factors), Q-squared will be comparable in value to R-squared.