Performance output - what is the +/- value?

Rachel_dvm

Hello,

I have a quick question to which I couldn't find the answer by searching the other threads or the information available on the RapidMiner website. I'm not from a data science background but have been using RapidMiner for some classification using a few different machine learning processes. I have used cross validation and an example of the performance results is this (a very poor classifier for my data):

Precision: 95.06% +/- 6.06% (micro average: 94.76%) (positive class: true)

                                    True false         True true         Class precision

Pred. false                   3915                 587                  86.96%

Pred. true                    12                      217                  94.76%

class recall                  99.69%              26.99%       

I'm not concerned with the actual performance of the model but more the value I've bolded. What does this +/- range represent? I had originally thought it was a range of precision but the positive value is above 100%. Is this due to the class distribution difference?

Thank you in advance!

yyhuang

Hi @Rachel_dvm,

Suppose you have a 10 fold cross validation for your ML model, you will get 10 individual testing performances on each testing set. The  number after +/- is for the standard deviation out of the 10 testing performance. With 10 fold cross validated models, you will get the average performance as well. The average is the number before +/-.

Cheers,
YY

Rachel_dvm

Yes, that is right. I used 10 fold. Thank you, that makes sense! Is there anything you could refer me to read to confirm this? (I will need to convince my supervisor that it is the standard deviation)

MartinLiebig

Hi @Rachel_dvm,

https://academy.rapidminer.com/learn/video/validating-a-model roughly about minute 5:40.

Best,

martin