If you’re writing Knitr documents, then you need to create more variables. A lot more. I have been reviewing projects, and I am finding literally dozens of instances where an author changed his or her mind while working on whatever it was. You see something like this.

## Accuracy 0.9821

…

The resulting accuracy is 95%.

The author must have changed something in his or her design, and accuracy has improved. The R output and the supporting text do not line up.

Or another one I’ve seen often.

## Resampling: Cross-Validated (10 fold)

…

Our training control will use k-fold cross validation, where k = 5.

Obviously, the text of the document and the R output do not match! This is so easy to fix, too. Create variables and reference them in your R code and your text. For example, if we create a cv_num_folds variable, and reference that variable appropriately, we can avoid all future issues of code/text misalignment.

cv_num_folds <- 10
control_validation <- trainControl(method = "cv", number = cv_num_folds)

In our text, we can now write…

Our training control will use k-fold cross validation, where k = `r cv_num_folds`.

Our training control will use k-fold cross validation, where k = 10.

Please, clean up those reports!