A BSTRACT Performing controlled experiments on noisy data is essential in thoroughly understanding deep learning across a spectrum of noise levels. Due to the lack of suitable datasets, previous research have only examined deep learning on controlled synthetic noise, and real-world noise has never been systematically studied in a controlled setting. To this end, this paper establishes a benchmark of real-world noisy labels at 10 controlled noise levels. As real-world noise possesses unique properties, to understand the difference, we conduct a large-scale study across a variety of noise levels and types, architectures, methods, and training settings. Our study shows that: (1) Deep Neural Networks (DNNs) generalize much better on real-world noise. We hope our benchmark, as well as our findings, will facilitate deep learning research on noisy data. 1 I NTRODUCTION Y ou take the blue pill you wake up in your bed and believe whatever you want to believe. Y ou take the red pill and I show you how deep the rabbit hole goes. Remember, all I'm offering is the truth. Morpheus (The Matrix 1999) Deep Neural Networks (DNNs) trained on noisy data demonstrate intriguing properties. For example, DNNs are capable of memorizing completely random training labels but generalize poorly on clean test data Zhang et al. (2017). When trained with stochastic gradient descent, DNNs learn patterns first before memorizing the label noise Arpit et al. (2017). These findings inspired recent research on noisy data. As training data are usually noisy, the fact that DNNs are able to memorize the noisy labels highlights the importance of deep learning research on noisy data. To study DNNs on noisy data, previous work often performs controlled experiments by injecting a series of synthetic noises into a well-annotated dataset. The noise level p may vary in the range of 0%- 100%, where p 0% is the clean dataset whereas p 100% represents the dataset of zero correct labels.