I'm working with a really imbalanced binary classification dataset so I decided to use SMOTE for only on the train data. Class rates were 95% -5% before SMOTE and 75-25% after SMOTE. In other words, I achieved a class balance ratio of 3: 1 (majority class: minority class). But I could not find any scientific evidence that indicates how much this ratio of class imbalance should be. In several studies, it has been said that 3: 1 imbalance ratio is sufficient, but is there any article you can recommend to me on class imbalance ratio?
Thank you.