Model with dummy variables has 100% accuracy?

I made a classification model using logistic regression. At first, i used data set that has some nominal variables. Since my task says that i should convert nominal to numeric variables, i used dummy coding in Nominal to Numeric operator, to do that.. Then i saved that file and make a model just like in the pics, but all the time i get accuracy 100%, so something is not ok. Before i did dummy coding, accuracy was 82% with the same model.Process
Cross Validation
Answers
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Hi,
you most likely overtrained. Try to put nominal to numerical into X-val and use group models to get it over. Keep in mind that X-val is only validating what's inside her.
Every time you extract something from the whole data set and get a transformation from it you technically need to do it INSIDE of x-val. This includes replacing of missing values with averages, normalization but also dummy coding. But it's rare that the effect is that extreme.
Best,
Martin
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