Often when I read ML papers the authors compare their results against a benchmark (e.g. using RMSE, accuracy, …) and say “our results improved with our new method by X%”. Nobody makes a significance test if the new method Y outperforms benchmark Z. Is there a reason why? Especially when you break your results down e.g. to the anaylsis of certain classes in object classification this seems important for me. Or do I overlook something?
Cross-validation is a reasonable alternative, however, it does increase your compute cost 5-10 times, or, more likely, means that you generate 5-10 times smaller model(s) which are worse than you could have made if you’d just made a single one.