update

README.md

@@ -94,8 +94,10 @@ This is a great documentary!
 
 ### Training Data / Preprocessing
 
-The data used comes from the Stanford NLP 🤗 hub. It has been preprocessed to only contain reviews at least 13 or more words in length. The model card 
-can be found [here](https://huggingface.co/datasets/stanfordnlp/imdb).
+The data used comes from the Stanford NLP 🤗 hub. The model card can be found [here](https://huggingface.co/datasets/stanfordnlp/imdb). This dataset is preprocessed in the 
+following way: The train and test splits are tokenized, concatenated, and chunked into chunks of 256 tokens. We subsequently load the training data into a `DataCollator` that 
+applies a custom random masking function when batching. We mask of 15% of tokens in each chunk. The evaluation data is masked in its entirety, to remove randomness when evaluating,
+and passed to a `DataCollator` with the default collating function.
 
 ### Training Procedure